Keynote Proceeding Nanocon 014 Pune.pdf

Bharati Vidyapeeth Deemed University Pune (India)

A' Grade University Status by MHRD, GOI l 'A' Grade Accredited by NAAC

Keynote ProceedingKeynote Proceeding

rd3 International Conference NANOCON 014 Smart Materials, Composites, Applications and New Inventions

rd3 International Conference NANOCON 014 Smart Materials, Composites, Applications and New Inventions

th thDate: 14 , 15 October, 2014

In Association with

North Carolina A&TState University

High Research Activity The University of Tokushima

rd3 International Conference on Smart Materials, Composites, Applications

and New Inventionsth thDate: 14 , 15 October, 2014

Keynote Proceeding

Bharati Vidyapeeth, Pune (India)

Maharashtra has a very old and well nurtured tradition of private participation in higher education. There are quite a few, even century old educational institutions, in Maharashtra which have moulded the generation of learned notables in the field of politics, industry, arts, music, sports, literature, social works and the like.

Dr. Patangrao Kadam taking inspiration from the leaders of earlier generations and realizing that social transformation can be brought about through the medium of education

thestablished Bharati Vidyapeeth. It was established on 10 May 1964 with the sole objective of bringing about intellectual awakening and all round development of the people of this country through education. Bharati Vidyapeeth, the parent body of Bharati Vidyapeeth University has been doing the momentous work of enhancing the accessibility of higher education and making it available to different sections of the population since the last four and a half decades.

Recently Bharati Vidyapeeth has completed its 50 years of establishment. It has created history by establishing itself as a leading educational institution in the country with 170 educational units imparting education from Pre Primary to Doctoral level. The endeavor of Bharati Vidyapeeth has always been to make available to the students a wide variety of academic options. Bharati Vidyapeeth has started Colleges / Institutions imparting education in almost all conventional as well as emerging disciplines. The institutions established cater to different disciplines such as Medicine, Dentistry, Ayurved, Homeopathy, Nursing, Arts, Science, Commerce, Engineering, Pharmacy, Management, Social Sciences, Law, Environmental Science, Architecture, Hotel Management and Catering Technology, Physical Education, Computer Science, Library Science, Information Technology, Biotechnology and Agriculture and Performing Arts. It is also one of the few private educational institutions in the country which has

started its own research institutes. It has three research institutes in the areas of Health Sciences, Pharmaceutical Science and Social Science.

Above educational institutions, which cater to the educational needs of thousands of students coming from different parts of India and also abroad, are spread around India in various cities viz. Pune, Navi Mumbai, Kolhapur, Solapur, Sang!i, Karad, Panchagani, New Delhi and rural area such as Jawahar in Thane district. All the institutions have achieved an acclaimed academic excellence and the teaching faculty in these institutions includes highly qualified, experienced, dedicated and student-caring teachers. The spectacular success achieved by the institutions and, thus, the Vidyapeeth is mainly a creation of unusual foresight, exceptionally dynamic leadership and able guidance of the founder, Hon'ble Dr. Patangrao Kadam.

The educational institutions of this Vidyapeeth have become nationally known for their academic expertise. They have established their academic reputation to such an extent that they have become the preferred destination for admissions not only for the students coming from different parts of India but also from abroad. In recognition of the academic excellence achieved by these institutions and the potential for development, which they posses, the Department of Human Resource Development, Government of India and the University Grants Commission of India have accorded the status of "Deemed University" to the 32 constituent units of Bharati Vidyapeeth.

Bharati Vidyapeeth is a model for emulation by others who would like to venture and start self financing institutions of higher education maintaining high level of academic excellence.

Bharati Vidyapeeth University (BVU)'A' Grade University Status by MHRD, GOI l 'A' Grade Accredited by NAAC

Dr. Patangraoji Kadam, renowned educationist and visionary established Bharati Vidyapeeth in 1964 with the motto "Social Transformation through Dynamic Education." Now 170 institutions impart education at all levels. His vision of establishing a university was realized

thwhen on 26 April 1996, the MHRD, New Delhi on the recommendations of the UGC has conferred the status of Deemed to be University to a cluster of 12 units of Bharati Vidyapeeth in appreciation of their academic excellence and potential for further growth, which led to the establishment of Bharati Vidyapeeth Deemed University. Presently, Bharati Vidyapeeth University has within its ambit 29 constituent Units.

Bharati Vidyapeeth University has become, perhaps, the largest multi-disciplinary, multi-campus, university in India. In addition, Bharati Vidyapeeth University is the only university in the country that comprises of research institutes besides the colleges for professional education.

Academic Programmes

Today, the University is one of the largest multi- disciplinary institutions of higher education in India having 29 constituent institutions located in eight sprawling campuses which together offer 278 plus academic programmes in 12 disciplines. It offers presently, 44 undergraduate and 104 postgraduate programmes. In addition, the University offers 37 programmes at Diploma level. With the academic autonomy it possesses, the University has introduced quite a few programmes in the emerging areas and also those of innovative nature; e.g. postgraduate programme in Geo-Informatics, Hospital Administration, Nanotechnology etc.

Research

Since its inception, this university has put a great deal of emphasis on research. It has nurtured research culture on its campuses and has provided inputs to the research activities in all the possible ways. One of the distinguished features of this University is the three specialized research institutions that it runs with its own funds. These institutions are Interactive Research School of Health Affairs (IRSHA), Institute of Research in Pharmaceutical Science and Applied Chemistry and Yashwantrao Chavan Institute of Social Science and Research.

In the last academic years, the faculty have published 1438

'A' Grade University Status by MHRD, GOI

Reaccredited with A Grade By NAACth35 Rank by India Today

research papers of which 873 are in international journals and 565 in national journals. Furthermore, 460 of these research papers are listed in SCOPUS database. The University has received Rs. 27.56 crore as research grants from various funding agencies for 147 research projects undertaken by the faculty. In addition, College of Pharmacy, Pune has received a funding of Rs. 2.5 Cr. from the Ministry of Food Processing, Government of India, especially for establishing a Food Testing Laboratory. One major initiative taken by the University during last two years is that of providing substantial seed money to faculty to undertake minor research projects. The relevance and applied nature of the research is evident from 44 patents.

The University has a vibrant in-house research programme leading to the Degree of Ph.D in as many as 71 subjects coming under 12 faculties. Presently, 628 students have registered under the supervision of 359 faculty of the University. Till today, 286 students have been awarded Ph.D Degree. The University has organized a total of 168 conferences / seminars / workshops / symposia at national and international levels together.

Elite and Distinguished Achievements and Activities

In October 2012, the Ministry of Human Resource Development (MHRD), Govt. of India, New Delhi has placed the University in 'A' Grade status. The academic excellence of the University is also acknowledged by National Assessment and Accreditation Council (NAAC) by awarding 'A' Grade, first in 2004 and recently in 2011. The UGC has granted 12(B) status to the University, thus making it eligible for research and travel grants.

The National Board of Accreditation (NBA) has accredited the undergraduate programmes conducted by our Poona College of Pharmacy, Pune for 5 years and those conducted by the College of Engineering for 3 years and the MBA programmes conducted by Institute of Management and Research, New Delhi for 3 years.

The College of Engineering, Pune has been selected for a grant of Rs. 4.00 Cr. under Technical Education Quality Improvement Programme of MHRD, Government of India, under the category of self-financing institutions. This programme is supported by the World Bank. This college is one of the top 25 colleges in India selected for this grant out of 236 colleges, which were eligible for the same.

The College of Engineering, Pune, Institute of Management and Research, New Delhi and Abhijit Kadam Institute of Management and Social Sciences, Solapur were awarded ISO certifications.

The University has introduced many examination reforms including the Choice Based Credit System (CBCS) at the postgraduate level and it is being extended to other programmes

The constituent institutions in Engineering, Law, Management, Pharmacy and Dentistry have been consistently ranked among the Top Colleges in respective disciplines in India.

The University caters to the needs of students from rural and urban areas through distance education.

The University has established a Women's Study Centre which conducts various self consciousness generating activities; does counseling to Women's Self Help Groups; carries out research projects; has brought out nationally acknowledged publications. It also organizes public lectures. The University provides substantial financial assistance to the deserving poor girl students.

Academic and Industry Collaborations:

The University has so far signed 95 MoUs for collaborations

of various kinds with renowned institutions such as NCAT in the USA, Sussex University in the UK, University of Venice in Italy and University of Cologne in Germany. The University has also developed its network with nationally renowned organizations such as NCL, Bio-Ved and Tata Consultancy. The above collaborations and networks, which have been developed by the University, focus on research, faculty exchange and development, consultancy and faculty and student training.

Overseas Students

The University rightly boasts of its 1600 faculty, 2000 supporting staff, more than 23,000 degree candidates hailing from all over India and other nations of the world. The constituent units of the University have world-class infrastructure, which caters to the needs of its faculty and students. This attracts students not only from various parts of India but also from abroad. At present the University has 1498 students from 47 countries enrolled in various programmes. To cater to the needs of these students, the University has established an International Student Cell. In

Organizer

OrganizerBharati Vidyapeeth University,College of Engineering (BVUCOE)

run by the College are approved by Institution of Engineers, Kolkata.

Academic Programmes

At present, it offers 10 programme at undergraduate level in Chemical, Civil, Computer, Electrical, Electronics, Electronics & Telecommunication, Information Technology, Mechanical, Production and Bio- Medical and 8 programmes at postgraduate level in Chemical, Civil, Computer, Electrical, Electronics, Information Technology, Mechanical and M.Tech (Nanotechnology), has been recently been started in collaboration with JSNN and NCA&T State University, Greensboro, USA. Under this collaboration five students of M.Tech (Nanotechnology) gets opportunity to pursue dissertation research at Joint School of Nanoscience & Nanotechnology (JSNN) USA with scholarship of $1000/ per month. The College is a recognized center for PhD programme.

In addition, the College is an Institution of Engineers' approved center for conducting workshops and practicals for students from the AMIE.

Research and Development

The College possesses a strong Research and Development (R&D) Department with a vision and mission to pursue and promote Research in Frontier Technology disciplines. Grant received till date is worth Rs 4.265 cr.

As the result of constant efforts taken in the research and development activity, the college has to its credit many publications in the international peer reviewed journals and national journals. The faculty members have also presented a large number of research papers in the reputed international and national conferences. The college has total 1155 research papers to its credit, out of which 635 research papers were published in international journals, 75 research papers in national journals and remaining research papers were presented and published at various national as well as international conferences.

As an outcome of the research activities conducted, the institute has got 2 national patients applied for one international patent in the USA, and 9 national patents in India. Globally, one of the major thrust areas is in emerging Nanotechnology Sector; especially on

Bharati Vidyapeeth University College of Engineering, Pune, established in the year 1983, is one of the oldest colleges having highest intake capacity in the state of Maharashtra. Over the last 30 years the College has made all round progress and is now acclaimed as one of the best engineering colleges in this part of the country.

The college is a constituent unit of Bharati Vidyapeeth Deemed University, which has got 'A' grade University status by Ministry of Human Resources Development (MHRD), Government of India, New Delhi, 'A' Grade accreditation by National Assessment and Accreditation Council (NAAC) in 2011 & 2004,'12 B' certification from University Grants Commission (UGC) New Delhi.

st21 Rank by DATA QUEST-CMR among Technical School.

Rank 35th level by 'India Today' (June 3,2013 ).

In annual surveys conducted by DATA QUEST-CMR of technical schools in India, the college has been consistently ranked among top 50 technical schools in

thIndia. This year, the college has been ranked 21 . It is also ranked amongst the top 5 technical colleges of West Zone, and also figures in the top 5 in India for HR

thperception (Excluding IITs). This is the 7 consecutive year that the College has featured in the top 50.

thRank 45 in servey conducted by AICTE-CII for Industry Institute Interaction

Selected (TEQIP-II) program by (MHRD) New Delhi.

Another feather in the cap of this College is that it has been selected by Ministry of Human Resource Development (MHRD) for the funding under the Technical Education Quality Improvement Program (TEQIP-II) program that is supported by the World Bank. Under the scheme, the College has been granted a total funding of Rs. 4.0 crores for the faculty as well as infrastructural development.

The College became a constituent unit of BVU from July 2000 onwards. All programmes conducted in the College are accredited by National Board for Accreditation (NBA) twice. The College has also been ranked as 'A' grade Engineering College by the Government of Maharashtra. In addition, all courses

Composite Materials. The College has established a center of composite materials and research is being carried out in association with North Carolina A& T State University, USA.

Academic and Industry Collaborations

Being a leading institution, it is extremely important to be connected with industries and academic institutions in India and abroad. The college has strong association with National as well as International companies / educational institutions. The College has signed Memorandum of Understanding (MoU's) with North Carolina A& T State University, U.S.A, University of Venice, Italy, Actel Corporation, U.S.A., iCarnegie, USA, Oracle India Ltd, India, Information & Systems Technology, India, Tata Consultancy Services, India and SKF India Limited, India. The above collaborations, which have been developed by the College, focus on research, faculty exchange and development, consultancy and student in-plant training.

The college, established in 1983, is one of the oldest and largest Engineering Colleges in the State of Maharashtra.

lRanked among top 50T Schools of India - DATAQUEST-CMR survey continuously for 7 years.

lPlacement among Top 20T Schools of India - DATAQUEST-CMR survey.

lAccreditation of the programs by National Board of Accreditation(NBA),New Delhi.

lSelected under Technical Education Quality Improvement Program, Phase II (TEQIP II) by Ministry of Human Resources Development (MHRD), Government of India, supported by World Bank for the grant of Rs 4 crores.

lCollaboration with North Carolina A&T State University, USA for faculty development and Research.

l

association with North Carolina A&T State University, Greensboro, USA, Tuskegee University, Alabama, USA and Center for Materials for E lectronics Technology, Depar tment of Information Technology, Government of India.

lOpportunity for students to complete dissertation at International Universities.

lInteraction with 396 industries for Inplant Training.

lThe college has its own spacious, well designed. building admeasuring 26,286 sq.m located within the campus. a healthy Student to Book Ratio as 1:22.

lThe college houses 110 Laboratories,43 Class Rooms and 21 Tutorial Rooms.

lFive storied library with more than 50,000 books, 15,000 volumes 70 National/71 International Journal subscriptions and Digital library facility.

lA unique master programme in Nanotechnology in association with Joint School of Nano Science and Nano Technology (JSNN) North Carolina A&T State University (NCAT), USA.

lGuidance to students for Robotics by experts from iCarnegie Powered by Carnegie Mellon University, USA.

lMore than 300 campus placements in 75 companies.

lResearch grant to the tune of 1.7 Crores in last six years.

lState of Art Laboratories with investment of 75 million INR in last six years.

lExperienced and qualified faculty members.

lThe training and Placement Section of the Institute is actively interacting with different Industries for organising Campus Placements.

lTraining for students in the areas of Personality

Organising biannual International Conference, in

Bharati Vidyapeeth University,College of Engineering (BVUCOE)

Manufacturing of glass /epoxy nanocomposite with Vacuum Assisted Resin Transfer Molding(VARTM)

Manufacturing of nylon 6 nanofibres by electrospinning process

1 Dr. Hitoshi Takagi Keynote 1 -Mechanical performance of green 02nanocomposites reinforced with cellulose nanofibers

2 Dr. Barry L.Burks Keynote 2 - Engaging Private Industry in 10University Research

3 Dr. Ajit Kelkar Keynote 3 -Nanoengineered materials for future 14 aerospace structures

4 Dr. Li-Chyong Chen Keynote 4 -Graphene oxide based visible light 18photocatalyst for photocatalytic CO reduction to 2solar fuels

5 Dr. Neil John Coville Keynote 5 -New directions for spherical carbons 26

6 Dr. Toshihiro Moriga Keynote 6-Control of Optical Properties of Oxynitride 32Pigments and Phosphors through Stoichiometries

7 Dr. Vijay Jain Keynote 7-Manufacturing: Vision for future 36

8 Prof. Ram Mohan Keynote 8 -Modeling at Nanoscale - Materials and 38Mechanics Applications, Potentials, and Challenges

9 Dr. Mikito Yasuzawa Keynote 9-Immobilization of enzyme using electrodeposition 40technique for biosensor application

10 Dr. Jitendra Kumar Pandey Keynote 10-Nano-particles from plants: Opportunities and 44Challenges

11 Dr. Alva Tontowi Keynote 11-Experimental Study on NanoBiocomposite of 48[nHA/Bioplastic] for Building a Porous Block Scaffold

12 Dr. James Ryan Keynote 12 -Economic Outreach and Engagement through 58Academic Research

13 Dr. Shaik Jeelani Keynote 13 -Recent Advances in the Materials Science and 62Engineering Research at Tuskegee University Tuskegee,Alabama

14 Dr. Dinesh Amalnerkar Keynote14 -Innovative biofilm inhibition & anti-microbial 68behaviour of molybdenum sulfide nanostructures generated by microwave-assisted solvothermal route

15 Dr. Tae Gyu Kim Keynote 15 -Conductive CVD Nano Diamond for application 70 of Cutting Tools

16 Dr. Katia Vutova Keynote 16 -Computational modeling and optimization 72approach at material treatment by electron beams

17 Dr. Malik Maaza Keynote 17 -Multi-functionality of VO Based 782Nanostructures in Photonics & Solar Energy

INDEX

Name of SpeakerSr. No Topic Page No.

INDEX

Name of SpeakerSr. No Topic Page No.

18 Dr. Nakagaito Antonio Norio Keynote 18 -Bionanocomposites based on cellulose 82

19 Dr. Yeng Ming Lam Keynote 19 -Excitonic Solar Cells - Challenges and 86Opportunities

20 Dr. Ron Naaman Keynote 20 -The Chirality Induced Spin Selectivity (CISS) 90 Effect- From Spintronics to Electron Transfer in Biology

21 Dr. Daisuke Yonekura Keynote 21 -Stability of ZnO/self-assembled gold 96nanoparticle network film

22 Dr. A.Subrahmanyam Keynote 22 -Plasma Processing of Nano-Matter: 106An over view

23 Dr. Amanullah Fatehmulla Keynote 23 -Nanostructured Materials and 110Nanocomposites

24 Dr. Pankaj Madhukar Koinkar Keynote 24 -Field Electron Emission investigations of 112Polypyrrole film

25 Dr. Mahesh V. Hosur Keynote 25 -Synergistic Effect of Nanoclay and MWCNTs 118on the Performance of Epoxy and Carbon/Epoxy Nanocomposites

26 Dr. (Mrs.) Lia Addadi Keynote 26 -Biogenic Mineralized Nanomaterials: 126Ancient Technologiesfor the Future

27 Prof. Yun-Hae Kim Keynote 27 -Processing and Mechanical Properties 132of Nanocomposites Based on Halloysite Nanotube and Unsaturated Polyester Resin

28 Dr. Eugenio Coronado Keynote 28 -Smart molecular materials: From bulk materials 140to nanomaterials.

29 Dr. Jatinder Yakhmi Keynote 29 -'NANO' and 'BIO' for movement and life 144

30 Dr. Vivek Polshettiwar Keynote 30 -Nanocatalysis for Sustainable Energy and 148 Green Environment

31 Dr. Masao Nagase Keynote 31 -Graphene on SiC substrates fabricated by an 154infrared rapid thermal annealer

32 Dr. Pawan Khanna Keynote 32 -Nano-structured Materials- The 160Chemical Way Quantum Dots And Metal-polymer Nanocomposites

33 Dr. A. K. Tyagi Keynote 33 -Nanomaterials, Nanostructures and 166Nanocoatings: Synthesis, Characterization and some Applications

3rd International Conference Nanocon 014 Smart Materials, Composites, Applications and New Inventions Date:14th, 15th October, 2014

Professor, Department of Mechanical Engineering, The University of Tokushima, Japan.

Email : [email protected]_u.ac.ip

Dr. Hitoshi Takagi

Research Area Mechanics of green composite materials, interface/interphase characterization innatural fiber-reinforced composites, functionality of natural fiber composites, andfiber surface modification for controlled adhesion

Qualification Ph.D., Hiroshima University, Japan, Sep. 1993

Awards & Honors Hatakeyama's Young Scientist Award of Japanese Society of Mechanical Engineers,Japan,1982

Young Scientists Award of Composites Division In The Japanese Society of Materials Science, Japan,1999

Best Paper Award of Composites Division In The Japanese Society of Materials Science, Japan,2002

Best Paper Award of Composites DivisionIn The Japanese Society of Materials Science, Japan,2008

Best Poster Presentation Award of Asian Workshop on PlasticProcessing, Malaysia, 2009

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SESSION 1A: Thin Films - I

3rd International Conference Nanocon 014 Smart Materials, Composites, Applications and New InventionsDate:14th, 15th October, 2014

Date : 14 October, 2014 Time : 11.20 11.35

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Mechanical performance of green nanocomposites reinforced with cellulose nanofibers

Dr. Hitoshi Takagi

Abstract

In this study, a green nanocomposites of polyvinyl alcohol (PVA) reinforced with cellulose nanofibers (CNF) weredeveloped and their mechanical properties were evaluated. Pre-molding nanocomposite sheets were obtainedby drying a mixture of aqueous solutions of CNF and PVA. CNF-reinforced PVA nanocomposites were fabricatedby laminating a number of pre-molding sheets. However, the surface of the pre-molding sheets would containtiny air bubbles. It was considered that the presence of the air bubbles on the surface of the sheets is responsiblefor the reduction of mechanical performance of the resulting nanocomposites. Thus, in this study we investigatedthe mechanical properties of CNF-reinforced PVA nanocomposites and examined the effects of the presence ofair bubbles generated during the fabrication process of this material on its mechanical properties. The effect ofdifferent parameters such as CNF loading on the mechanical properties was also discussed.

Keywords : Given nano composites, celluosenanofiber, natural fiber biodegradable polymer

1. Introduction

We are now using a wide variety of plastics and plastic-based materials; such as glass fiber reinforced plastics(GFRP). These plastic-based materials are largely made from fossil resources; such as petroleum and coal. Thetotal volume of the plastic products has been increasing year by year. Recently increasing attention has been paidto plastic waste problems as well as resource depletion problems in a global scale [1]. In order to build asustainable and prosperous society, we have to change the source of raw materials from exhaustible resource toreproducible one, and should use bio-based materials. Therefore research and development of natural fiberreinforced polymer composites have been carried out over a worldwide scale [1]. Several kinds of natural fiber-reinforced composites exhibit fully-biodegradable nature, which are often called "green composites", andtherefore they can be easily disposed off after use, and at the same time there is no additional greenhouse gasemissions even after burning out (so-called carbon neutrality) [2, 3].

Most of initial research works on the development of green composites have been handled macroscopic naturalplant fiber as a reinforcing phase [4-11]. In the case of macroscopic natural fibers, they have often suffered fromvarious kinds of damage introduced during manufacturing, resulting in lower mechanical performance with widescattering in mechanical performances. On the contrary, in the case of nanoscale fiber such as cellulosenanofibers (CNFs) or cellulose microfibrils, which are extracted from pulp by applying very high shearing forceby using a high pressure homogenization process, it is believed that they have relatively high performance.Therefore the cellulose nanofibers have attracted a great deal of researchers' attention [12-18].

Yano and Nakahara fabricated starch/microfibrillated pulp composites by a press forming technique, andevaluated their flexural properties as a function of water retention, which is thought to be one of the mosteffective indices for the degree of microfibrillation [16]. They also described that the mechanical propertiesdepended strongly on the degree of fiber microfibrillation; namely the reinforcing fibers' fineness.

Nakagaito et al. fabricated high-strength micro-fibrillated cellulose fiber-reinforced phenolic composites havingtensile strength of 370 MPa and Young's modulus of 19 GPa [12]. Fully biodegradable cellulose nanofiber-reinforced starch-based composites were also developed, and reported that the mechanical properties of thecomposites were affected by the processing conditions [13]. Omrani et al. fabricated cellulose nanofiber/epoxycomposites having a maximum fiber content of 5wt%, however they did not carry out tensile tests, but onlydynamic mechanical thermal analysis [14].

Takagi and Asano also made chemically modified starch-based resin/CNF green nanocomposites by hot-pressing method, and examined the effect of processing conditions on the flexural properties of resultant greennanocomposites [13]. They pointed out the importance of uniform dispersion of nanofibers in the resin matrix.

In this study, a green nanocomposite material of polyvinyl alcohol (PVA) reinforced with CNF was developed andthe strength properties were evaluated. Pre-molding sheets (i.e. preform sheets) were obtained by drying amixture of aqueous suspensions of CNF and PVA. CNF-reinforced PVA-based green nanocomposites were


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fabricated using a hot press by laminating a number of sheets inside a mold. However, the surface of the dry pre-molding sheets would contain many tiny bubbles. It was considered that the presence of the air bubbles on thesurfaces of the sheets is responsible for the reduction in the mechanical performance of the resulting composites.Therefore we investigated the mechanical properties of CNF-reinforced PVA and examined the effects of thepresence of bubbles generated during the fabrication process on the composites' mechanical properties. Theeffects of different parameters such as filler load on the mechanical properties were also discussed.

2. Material and methods

2.1 Materials

Thin slurry containing 90wt% water and 10wt% CNF (Celish KY-100G, Daicel Cooperation, Japan) (Fig. 1) wasused as the reinforcing material of PVA (RS-2117, Kuraray Co. Ltd., Japan). Figure 2 shows a SEMphotomicrograph of the CNF used in this study. Before preparing the PVA-CNF suspension mixture with apredetermined CNF loading, a dilute suspension of CNF in water (CNF suspension) and a solution of PVA in waterwere made using the following sequences.

2.1.1 Preparation of CNF suspension

For the preparation of CNF suspension, 20.0 g of CNF and 450 ml of water were stirred in a beaker using amagnetic stirrer at 600 rpm for 24 hours at room temperature. During this mixing process, the beaker wascovered with a sheet of thin plastic film to prevent water evaporation.

Fig. 1 Macroscopic photograph of KY-100G

Fig. 2 SEM photograph of KY-100G

Date:14th, 15th October, 2014

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3rd International Conference Nanocon 014 Smart Materials, Composites, Applications and New Inventions

2.1.2 Preparation of PVA solution

For PVA solution, 500 ml of water in a beaker was heated to 90C using a mantle heater. When the watertemperature reached 90C, PVA powder was gradually added in the hot water, and was dissolved while stirringwith a glass rod. The final PVA concentration of the CNF suspension was calculated by the ratio of the weightsof PVA powder added and resultant CNF suspension.

2.2 Fabrication of pre-molding sheets

First, CNF suspension and PVA solution were mixed and stirred at 500 rpm for 10 minutes with a magnetic stirrer.The liquid mixture was poured into a heat-resistant 300 mm by 240 mm plastic tray. Then, the tray containingthe liquid mixture was dried by using a convection-type oven at 70C for 24 hours and finally pre-molding sheetswere peeled off from the plastic tray.

2.3 Vacuum stirrer treatment

During the stirrer mixing treatment described in the section 2.2 many small air bubbles could be seen in thesolution, and therefore the bubbles were also formed on the surface of the resultant pre-molding sheets afterdrying. To avoid these small bubbles, a vacuum stirrer treatment was applied to the CNF-PVA mixture. Theprocess chart is shown in Fig. 3.

Fig. 3 Process chart for fabrication


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2.4 Green nanocomposites fabrication

The dried pre-molding sheets were cut into strips sized 100 mm by 10 mm. These strips were then laminatedand set in a metallic mold. Next the laminated sheets were hot-pressed at 210C, under 10 MPa, for 10 minutes,and cooled down before specimens were removed from the metallic mold. Then, small burrs at the specimenedges were removed with sandpaper, and finally paper tabs of 35 mm by 10 mm were attached with adhesiveon both extremities of the specimens.

2.5 Mechanical characterization

Quasi-static tensile tests were performed with an Instron universal testing machine (Model 5567, InstronCorporation, USA) at a cross-head speed of 1.0 mm/min with a gauge length of 30.0 mm at room temperature(Fig. 4).

2.6 Surface characterization

The fracture morphology of composites and fibers was examined by an optical microscope (SZH-10, Olympus,Japan) and scanning electron microscope (SEM: S-4700, Hitachi, Japan). All samples were sputter-coated withgold/platinum prior to the SEM observation

3. Results and discussion

3.1 Effect of vacuum stirrer treatment

If the pre-molding sheets were produced without the vacuum stirrer treatment, small bubbles were observed onthe surface of the entire sheet as shown in Fig. 5. However when the vacuum stirrer treatment (vacuumdefoaming) was performed, bubbles were not visible at all on the surface of the pre-molding sheets (Fig. 6).

3.2 Mechanical properties

The pre-molding sheets obtained by vacuum stirrer treatment resulted in composites with higher mechanicalproperties as shown by the stress-strain curves in Fig. 7. Thus we can see that the presence of air bubblesgenerated during stirring and drying processes was one factor that reduced the tensile strength of CNF greennanocomposites. If the pre-molding sheets contain air bubbles, the surface has irregularities causing adhesionfailure when laminated to make the composites


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In addition, the tensile strength of the CNF composites fabricated from vacuum-stirrer-treated pre-moldingsheets was also affected when the CNF content was varied from 30 to 70wt%. According to Fig. 8, the tensilestrength is highest at 50wt% CNF content, but further increases in CNF content does not lead to higher strength.Similar dependence was also reported in the CNF-starch green nanocomposite system [15]. Their tensile strengthreached approximately 150 MPa, showing a possibility for engineering applications as structural materials.

Fig. 5 Macroscopic photograph of pre-molding sheet without vacuum stirrer treatment

Fig. 6 Macroscopic photograph of pre-molding sheet with vacuum stirrer treatment

Fig. 7 Typical stress-strain curves of CNF/PVA green nanocomposites


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3.3 Fracture behavior

The fracture surface of the composite with 50wt% CNF without defoaming treatment is presented in Fig. 9,showing a laminate cracking. This cracking might lead to reduction both in tensile strength and fracture strain.In addition, there are many small holes on the fracture surface as shown in Fig. 10. These holes seem to beformed by agglomeration of much smaller air bubbles dispersed in the PVA solution before drying.

Fig. 9 SEM photograph of the fracture surface of green nanocomposite (50wt%CNF, no vacuum-stirred)

Fig. 10 SEM photograph of the fracture surface of green nanocomposite (50wt%CNF, no vacuum-stirred)

Fig. 8 Typical stress-strain curves of CNF/PVA green nanocomposites as a function of CNF loading


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The fracture surface of the composites with vacuum stirrer treatment is presented in Fig. 11, there is no crackingon the fracture surface.

4. Conclusions

We successfully fabricated CNF-reinforced biodegradable green nanocomposites, and evaluated the mechanicalproperties of the CNF-PVA green nanocomposites and examined the effects of the presence of air bubblesgenerated during the fabrication process on their mechanical properties. The experimental results showed thatthe vacuum stirrer defoaming process is effective to obtain the CNF reinforced green nanocomposites withbetter mechanical performance. Their tensile strength reached approximately 150 MPa, showing a possibility forengineering applications as structural materials.

Acknowledgements

The authors wish to thank Mr. Tomoyuki Ueki and Mr. Satoshi Sugano (The University of Tokushima) for theirtechnical assistance in SEM observations.

References

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[2] H. Takagi, S. Kako, K. Kusano, and A. Ousaka, Adv. Compos. Mater. 16(4), 377 (2007)

[3] P. Wambua, J. Ivens, and I. Verpoest, Compos. Sci. Technol. 63(9), 1259 (2003)

[4] M. Wollerdorfer and H. Bader, Ind. Crops Prod. 8(2), 105 (1998)

[5] S. Luo and A. N. Netravali, J. Mater. Sci. 34(15), 3709 (1999)

[6] S. Luo and A. N. Netravali, Polym. Compos. 20(3), 367 (1999)

[7] P. Lodha and A. N. Netravali, J. Mater. Sci. 37(17), 3657 (2002)

[8] A. K. Mohanty, M. Misra, and G. Hinrichsen, Macromol. Mater. Eng. 276/277(1), 1 (2000)

[9] D. H. Mueller and A. Krobjilowski, J. Ind. Text. 33(2), 111 (2003)

[10] H. Takagi and Y. Ichihara, JSME Int. J. A-Solid. M., 47(4), 551 (2004)

[11] K. Liu, H. Takagi, and Z. Yang, Mater. Design. 32(8-9), 4586 (2011)

[12] A. N. Nakagaito and H. Yano, Appl. Phys. A-Mater. 80(1), 155 (2005)

[13] H. Takagi and A. Asano, Compos. Part A-Appl S. 38(4), 685 (2008)

[14] A. Omrani, L. C. Simonb, and A. A. Rostami, Mat. Sci. Eng. A-Struct., 490(1-2), 131 (2008)

[15] H. Takagi, Key Eng. Mat. 462-463, 576 (2011)

[16] H. Yano and S. Nakahara, J. Mater. Sci. 39(5), 1635 (2004)

[17] J. K. Pandey, H. Takagi, and A. N. Nakagaito, Compos. Part B-Eng. 43(7), 2822 (2012)

[18] J. K. Pandey, A. N. Nakagaito, and H. Takagi, Polym. Eng. Sci. 53(1), 1 (2013)


Vice ChancellorNorth Carolina Agricultural and Technical State University, USA.

Email. [email protected]

Dr. Barry L.Burks

Research Area Nuclear Physics

Qualification Ph.D., in experimental nuclear physics from the University of North Carolina at ChapelHill

Awards & Honors He has a broad perspective, based on more than 30 years experience conductingresearch, developing technology, leading projects and managing programs for theDepartment of Energy, Department of Defense, NASA, the commercial nuclearindustry, the automated manufacturing industry, and most recently university-basedapplied research.

President of TPG Applied Technology of Knoxville,Tennessee Associate director of theCharlotte Research Institute at the University of North Carolina Charlotte from 2007

Conference Chair of the American Nuclear Society Third Joint InternationalConference on Emergency preparedness & Response and Robotics for HazardousEnvironments, Knoxville,TN,August 7-10,2011

Recipient of the ANS RRSD 2008 /ray Goertz Award, for outstanding contributions tothe field of nuclear applications of Robotics and Remote Systems TechnicalAchievement Award, Gunite and and Associated Tanks Project ,September 2000

10

SESSION 1B : Special Topics - I (Nanostructured materials NT+Grapehene)



11

Engaging Private Industry in University Research

Dr. Barry L.Burks

North Carolina Agricultural and Technical State University (NCAT) is a doctoral research university and ahistorically black university located in Greensboro, North Carolina, United States of America (USA). The universityserves nearly 11,000 full time students making it the largest historically black college or university (HBCU) in theUSA. The university generates an average of $57 million dollars in sponsored research activities which also ranksnear the top of the list for HBCUs. Although the majority of this research funding comes from federal agenciesseveral million dollars per year are provided by private companies and other non-governmental organizations.Connecting students and faculty to private industry is extremely important to the mission of the university. Inaddition to the two core missions of teaching and research the university has a responsibility to serve thecommunity. Broadly speaking service to the community can take many forms including:

Creation of new companies and new jobs based on university generated inventions,

Providing access to specialized equipment for innovation and problem solving,

Providing expertise for planning and problem solving, and

Training the workforce needed for local and national industry.

Collaboration with industry can involve the four areas listed above but it goes beyond those possibilities.Experiential learning through internships, co-operative assignments, and industry sponsored research enhancesthe educational experience tremendously and also gives students a huge advantage when job hunting.Corporate relationships are obviously beneficial for job placement of graduates but these relationships are alsovital for developing philanthropic gifts, grants, and contracts.

Industry seeks collaboration primarily for access to graduates, faculty expertise, access to specialized equipmentand facilities, and also access to innovative ideas. Collaboration with universities is particularly beneficial forsmall companies who can not afford specialized equipment that might be used only occasionally for prototypedevelopment, for example, or infrequent characterization measurements. Unless the skills required to solve adesign or manufacturing problem are core to a company's mission it is much more cost effective to payuniversities to solve these problems than to hire the expertise.

Typical of research universities in the USA NCAT is engaged with private companies in a variety of partnershipsincluding philanthropy, internships, team teaching, industry sponsored senior design projects, sponsoredresearch, service for fee and teaming to seek third party funding opportunities. One example of engagementwith industry can be found in the National Science Foundation (NSF) sponsored Engineering Research Center(ERC) for Revolutionizing Biometallic Materials. NCAT is the only HBCU to be selected to serve as the leadinstitution of the prestigious ERC. Industry affiliates partner with the center to gain access to students, faculty,equipment and ideas. The ERCs are long term programs intended to fund university lead innovation teams frominnovation to commercialization. Funding in the latter years of the programs is dependent on successfullypartnering with industry to ensure translation of ideas from the laboratory bench to commercial product. TheNCAT ERC demonstrated sufficient progress so that funding was extended for an additional 3 years beyond theoriginal 5 year duration. The ERC focuses primarily on development of medical devices made from magnesiumalloys which both promote healing and because of gradual absorption of the magnesium into the body don'trequire subsequent surgeries to remove the devices.

One feature of the North Carolina state university system that is not common elsewhere is that each stateuniversity is permitted to designate a parcel of land as a "Millenial" Campus. By law for activities that are locatedat the Millenial Campuses the universities are granted an exclusion from the Umstead Law which precludesuniversity competition with the private sector. The bottom line of this exception is that the universities canpartner with private industry in more flexible relationships including for example leasing space on thesecampuses to private companies. Value of the collaboration to both the university and private companiesincreases dramatically from being co-located and sharing access to certain facilities.


12

SESSION 1B : Special Topics - I (Nanostructured materials NT+Grapehene)

The main campus of NCAT and the main campus of the University of North Carolina at Greensboro (UNCG) arelocated in close proximity to one another. The two universities share a Millenial Campus called the GatewayUniversity Research Park (GURP) also located in Greensboro. GURP is comprised of two 75 acre tracts that housea number of research facilities including the Joint School for Nanoscience and Nanoengineering (JSNN). TheJSNN offers graduate degrees only to Nanoscience students enrolled at UNCG and Nanoengineering studentsenrolled at NCAT. JSNN was founded to foster collaboration between the two universities and also to serve asthe anchor tenant at GURP to attract private companies interested in collaboration with the universities andaccess to the suite of instrumentation located at the JSNN.

In addition to the usual methods of engagement GURP created a Nanomanufacturing Innovation Consortium(NIC) that offers members access to JSNN equipment, acknowledgement on signage and presentations, accessto meeting and conference facilities, invitation to the NIC annual meeting and JSNN events, input into researchdirections and networking with researchers (facilitating hiring and licensing). The NIC members gain maximumaccess with minimum investment, minimizes issues with intellectual property, and enables networking amongnanomanufacturers. The NIC has enrolled 27 members as of September 2014.

In addition to the NIC GURP has created an organization called Gateway Materials Test Center (GMTC) as amechanism for performing service for a fee using the expertise and facilities at JSNN and additional personnelhired by the GMTC. The primary purpose of the GMTC is to conduct materials testing associated withcomponents of aircraft and also other systems that use composite structures though the testing is by no meanslimited to composite materials. The GMTC has completed verification testing to demonstrate results equivalentor improved over results provided at other well established test centers.

During the presentation the speaker will provide several specific examples of successful university-industrypartnership particularly emphasizing partnerships in nanotechnology applications.


13


Release of Souvenir of the conference by the chief patron, Dr. Patangrao Kadam, Hon Chancellor, Bharati VidyapeethDeemed University. (Left to Right) Dr. Anand Bhalerao, Prof. Jitendra Yakhmi, Dr. Ajit Kelkar, Dr. Shivajirao Kadam, Dr.Barry Burks, Dr. Patangrao Kadam, Dr. Ravi Grover, Dr. Shinichi Kikkawa, Dr. Vishwajeet Kadam, Dr. Reshef Tenne andDr. Dinesh Amalnerkar

Nanocon 012


Professor and Chair, NanoengineeringAssociate Director, Center for Advanced Materials and Smart Structures

Joint School of Nanoscience and Nanoengineering Greensboro, USAE-mail: kelkar@ ncat.edu, [email protected]

Dr. Ajit Kelkar

Research Area Atomistic Modeling , Nano Engineered Materials, Eletrospinning, Molecular DynamicSimulations, Nanotechnology, Multifunctional Materials, Crashworthiness, Low CostComposite Manufacturing (VARTM Processing), Mechanical Characterization ofMaterials including Metals, Polymeric Composites (Tape and Textile), Ceramics andCeramic Composites, Computer Aided Design and Modeling, Finite Element andFinite Difference Modeling, Numerical Analysis, Fatigue and Impact Modeling andTesting of Polymeric Composites, Ceramic Composites, Textile Composites,Micromechanics Modeling and Testing, Single Fiber Modeling and Testing

Qualification Ph.D., Mechanical Engineering, Old Dominion University, Norfolk, Virginia, 1985

M.S., Mechanical Engineering, South Dakota State University, South Dakota, 1981

B.S., Mechanical Engineering, Poona University, Poona, India, 1975

No. of Patents 2

No. of Publications More than 199

Refereed Conference Prodeeding : More than 173

Research Proposals More than 78Funded

Awards & Honors Special award from North Carolina A&T State University Division of Research andEconomic Development for the "Founding Member of ADVAERO, Inc.", a firstcompany that was spun of by A&T in the area of aerospace/composite, NC, April 2008

Recipient of the Best Paper Award-Automotive Division, Ansys Conference, Pittsburg,April 2006

Recipient of the Best FEA Image Award, CEIVIZ Conference, March 2006

14

SESSION 1C: Synthesis, Characterization and Applications - I


15

NANOENGINEERED MATERIALS FOR FUTURE AEROSPACE STRUCTURES

Dr. Ajit Kelkar

ABSTRACT

During the past decade use of both carbon and fiberglass composites have increased dramatically for aerospace,marine and automotive applications. Advances in conventional tape laminates and textile composites provideaircraft manufacturers important technology, but the industry lacks the confidence to use these composites tomanufacture primary load carrying structures due to low damage tolerance. One of the critical problems is failuredue to delaminations of composite laminates via low velocity impact loadings. To alleviate this problem, severalmethods which use applications of nano technology will be discussed. This talk will address various methods andmaterial systems for processing and integration of the nano material constituents, including: (a) dispersingalumina nanoparticles using high energy mixing (using ultrasonication, high shear mixing and pulverization) and(b) electrospinning technique to manufacture nanofibers. This newly developed reinforced polymernanocomposites and the processing methodologies have shown a promising means of improving theinterlaminar properties of woven fiber glass composites compared to the traditional methods such as stitchingand Z-pinning to improve interlaminar properties of woven composites.

The electro spinning technology creates nanoscale fibers with improved molecular orientation and the reductionin concentration of fiber imperfections and crystal defects. Electrospinning process utilizes surface tension effectscreated by electrostatic forces acting on liquid droplets, creating numerous nanofibers. These nano fibers areuseful as through the thickness reinforcing agents in woven composites. While the electrospun nanofibersprovide bridging through-the-thickness reinforcement, the use of the nanoparticles influences the thermo-physical properties and provides an effective means from commercially available nano level materialconfigurations to form reinforced polymer nanocomposites. Both these methods and material systems provideeffective means for integrating the nano material constituents into traditional fiber composite systems.

In addition to electrospun nanofibers and alumina nanoparticles, talk will cover development of novel resinsystem for multifunctional applications that require thermal and electrical conductivity, self-sensing and self-actuation capabilities without a loss of required mechanical properties. The talk will present fabrication andcharacterization efforts that are underway to use single wall boron nitride nano tubes (BNNT) reinforced epoxytowards the development resin system with improved thermal and radiation shielding properties. Effect of nanoconstituents dispersed into the resin as reinforcements on the thermal properties of resin will be addressed. Thetalk will cover analytical prediction of mechanical and thermal properties of single-walled boron nitride (BNNT)nanotubes reinforced epoxy resin (DGEBF) cross-linked with curing agent W (DETDA). The MD models of thereinforced epoxy were built using the amorphous module of Material Studio (Accelrys Inc.). The COMPASS forcefield was used in the simulations. The amorphous structure was achieved by using periodic boundary conditionsand then subjecting to an energy minimization using an ensemble of the constant-volume and temperature(NVT). The structures were equilibrated for 100 picoseconds (ps) and then followed by MD equilibrations at roomtemperature for another 200 ps. Since at room temperature most of the atoms are in static mode, the atomswere excited using simulation temperatures above the glass transition temperatures.

In an attempt of finding global energy minimum, simulated annealing runs were then carried out starting atelevated temperatures at atmospheric pressure using the ensembles of the constant number of particles,constant-pressure and constant temperature (NPT). The molecular structure temperature was then graduallylowered to a room temperature. Each subsequent simulation was started from the final configuration obtainedat the preceding temperature. Density of the epoxy at each temperature was calculated from the average specificvolume and glass transition temperature (Tg) was estimated based on the discontinuity in the slope of thedensity-temperature plot. The amorphous structures obtained at room temperature were analyzed to determinethe fundamental mechanical properties of the BNNT reinforced EPON 862-W. Calculations of fundamentalmechanical material properties of single-walled BNNT were performed using molecular dynamics simulations viaMaterial Studio. A simple but effective technique of extrapolation was adopted to compensate for the problemof BNNT distortion because of smaller lattice sizes. Property calculations were performed at each density valueand extrapolated to the actual value of density of BNNT. A similar extrapolation technique was employed toovercome the issue of achieving exact theoretical mixture densities of BNNT-Epoxy composites in the MDmodels.



16

SESSION 1C: Synthesis, Characterization and Applications - I

The proposed new materials will eventually help in the discovery, development and incorporation of improvednano composite materials with effective manufacturing methodologies for defense and industrial applications.In addition these materials will allow the full utilization of nanocomposites in not only reinforcing applicationsbut also in multifunctional applications where sensing and the unique optical, thermal, electrical and magneticproperties of nanoparticles can be combined with mechanical reinforcement to offer the greatest opportunitiesfor significant advances in material design and function.


17


Nanocon 012

Honble Chancellor Dr. Patangrao Kadam with International Deligates.


Professor, Distinguished Research fellow & Director,Center for Condensed Matter Science,

National Taiwan University, Taiwan.Email : [email protected]

Dr. Li-Chyong Chen

Research Area Nanomaterials, Plasma-assisted Processes, Chemical and Physical Vapor DepositionProcesses.

Optoelectronics, Energy, Sensing.

Qualification Ph.D., Applied Physics, Harvard,1989

Awards & Honors Acharya Vinova International Award in Materials Science and Technology for year2013, VBRI, India (2013)

Ho Chin-Tui Outstanding Scholar Award, Ho Chin-Tui Foundation (2012)

Outstanding Scholar Award, Foundation for the Advancement of OutstandingScholarship (2010-2015)

Outstanding Research Award, National Science Council (2010-2013, and 2007)

Fellow, the Materials Research Society, USA (2010)

Laureate of the Khwarizmi International Award, Iran (2009)

International Federation of Inventors' Association Lady Prize (2009)

Distinguished Visiting Research Fellow, Royal Academy of Engineering, UK (2008)

Outstanding Scholar Research Project, National Science Council (2008-2011)

Honorary Doctor, Linkping University, Sweden (2007)

Fellow, the Physical Society of ROC in Taiwan (2006)

Academia Sinica Young Scholar Research Award (2000)

18

SESSION 1D : Nanoelectronics - I


19


Graphene oxide based visible light photocatalyst for photocatalytic CO2 reduction to solar

fuels

Dr. Li-Chyong Chen

ABSTRACT

Artificial photosynthesis is one of the most anticipated solutions global warming and increasingly energydemands. Photocatalytic reduction of carbon dioxide with water to yield hydrocarbons (methane, methanol, etc.)on the surface of semiconductor catalyst has the potential to become a viable and sustainable alternative energysource to fossil fuel. This work describes a high photocatalytic conversion of CO2 to methanol using grapheneoxides (GOs) as a promising photocatalyst. The modified Hummer's method has been applied to synthesize theGO based photocatalyst for the enhanced catalytic activity. The photocatalytic CO2 to methanol conversion rateon modified graphene oxide is 0.172 mol g-cat-1 h-1 under visible light, which is six-fold higher than the pureTiO2 . Further, Cu and MoS2 nanoparticles were deposited on GO as co-catalysts to enhanced the photocatalyticreaction. Not only methanol, but also acetaldehyde was detected. Total solar to fuel yield of 6.8 mole g-cat

-1h-

1 has been achieved, which is 240 times enhancement relative to the commercial P-25 photocatalyst. In all theabove-mentioned hybrids, the photocatalytic performance is always much better than that of constituentcomponent when used alone.

Keywords: Graphene Oxide, Photocatalyst, CO2 reduction, Solar Fuels, Cu-nanoparticles, MoS2 nanoparticles.

Introduction

In this 21st century, the rising demand of the fossil fuels in our modern society emits vast quantity of carbondioxide (CO2). This increasing CO2 concentration is the most threatening environmental concerns associated withglobal warming and climate change1. Therefore, to find a solution converting stable CO2 into green energy fuelis the highly desirable approach for the sustainable energy research. The leading approaches for CO2 reductioninclude electrochemical reduction, photochemical reduction and thermal hydrogenation. Despite their individualtechnical merit, more fundamental research and physiochemical understanding are still required for eachapproach to improve their overall conversion efficiency and product selectivity for practical implementation. Thehigh kinetic barrier, primarily due to the stability of initial CO2, is one of the critical challenges to reduce CO2 toanother product effectively. Development of energy-efficient technologies for the reduction of CO2 to high-energy density fuels in an eco-friendly manner is also essential. In a broad sense, the biomimetic artificialphotosynthesis method is considered as a potential approach to recycle CO2. Interestingly, in this process, thehydrocarbons are produced by photoreduction of CO2 coupled with water and solar energy [1, 2]. In 1979, Inoueet al. first demonstrated the photocatalytic reduction of CO2 to form organic compounds by photosensitivesemiconductor [3]. After this pioneering breakthrough, several wide-bandgap semiconductor materials havebeen explored towards the photocatalytic CO2 reduction [4-10]. Among all the semiconductor materials, titaniumdioxide (TiO2) and some TiO2 based heterogeneous photocatalysts have been explored most extensively for thelast three decades due to their low cost, low toxicity and high chemical stability [11, 12]. Besides TiO2, severalnon-Ti metal oxides [13], metal sulfides [14] and a few homogeneous organometallic materials [15-18] werereported to exhibit more effective CO2 reduction under solar light irradiation. In CO2 photoreduction technology,the major challenge is the low efficiency of the photocatalyst. For instance, the reported methanol conversionrate for TiO2 in vapor phase, typically, is 0.02 mol g cat

-1h

-1only [19], which is far below the actual requirement.

To overcome this, several strategies have been adopted to enhance the photocatalytic activity of the wide-bandgap semiconductor materials [20-22]. Among them, the most popular technique is to dope thesemiconductor with noble metal co-catalyst as a charge-carrier trap, which suppresses the recombination ofphoto-excited electron-hole pair [23, 24]. However, the prospect of these materials is not satisfactory, due to thedisappointingly low quantum efficiency and lack of fuel-selectivity of the photocatalysts. Thus, it is a greatchallenge to develop a potential low-cost photocatalyst for a high CO2 reduction efficiency and simultaneouslyproducing desired solar fuel under visible light.

Graphene oxide (GO) is a newly emerging material of solution-dispersible polyaromatic, two-dimensional carbonsheets produced from acid exfoliation of graphite.18 Its like an insulating material with a wide bandgap, throughits electronic structure depends on the stoichiometric carbon-to-oxygen atomic ratio. The basal plane of the GO


20

covalently surrounded by the epoxide and hydroxyl groups, while edges were decorated with carboxyl functionalgroups [25]. Due to the presence of several types of oxygen containing functionality, on the basal plane and sheetedges the aromatic GO can undergo a complex interplay of covalent, noncovalent interactions with differentmolecules. GO based hybrids and composite materials with improved properties have been synthesized with arange of organic and inorganic molecules via covalent, noncovalent and ionic interaction. The oxygenatedfunctional groups provide a 2D network of sp

2and sp

3bonded atoms in GO, which lead to presence of finite

bandgap depending on isolated sp2

domains [26]. Tunability of the ratio of the sp2

and sp3

fraction by reductionchemistry can therefore, controllably transform the insulating GO to a semiconductor and to a graphene-likesemi-metal [27].

In 2010, Yeh et al. demonstrated GO as an active photocatalyst for water splitting application [28]. In our previousstudy, the result shows that the graphene oxide with the tuning bandgap is a promising photocatalyst for CO2reduction to methanol under visible light irradiation [29]. We have conducted a systematic investigation ofphotocatalytic CO2 reduction on various GO samples synthesized under different conditions. We found that themodified GO (GO-3), obtained by the modified Hummers method in the presence of excess KMnO4 and excessH3PO4 to raise the level of oxidation under the protection of GO basal plane, exhibits the highest photocatalyticefficiency among the studied samples. In Figure 1(a) the observed approximate band gaps of all the GOs,showing an intrinsic semiconductor like absorption in the blue optical region, are adequately large to overcomethe endothermic energy require for the CO2 reduction (-0.38 V), under solar energy excitation. The photocatalyticconversion rate of CO2 to methanol on GO

-3is 0.172 mol/ g cat

-1hr

-1under simulated solar-light source for 4 h,

which is six-fold higher than the pure TiO2 as shown in figure 1(c). We have been proposed the possiblephotocatalytic mechanism. Figure-1(d) presents the photocatalytic CO2 reduction to hydrocarbon by modifiedGO under visible light. Additionally, the isotope tracer analysis confirmed that the methanol was produceddirectly from the photocatalytic reduction of CO2 instead of any photo dissociation of the carbon containingcatalyst. The CO2 photoreduction reaction usually suffers from limited solar fuel conversion efficiency ofphotocatalyst that is due to the fast recombination and instability of the photo-generated electrons-holes pair.The bandgap of GO is too large for visible light response, and many methods such as doping with metal ionspreparing solid solutions and combining with various narrow bandgap semiconductors are the vital approachesto make GO visible light active.

In general, CO2 photoreduction reaction suffers from limited solar fuel conversion efficiency of photocatalyst dueto the fast recombination and instability of the photo-generated electron-hole pairs. For GO, though the superiorto TiO2 performance is encouraging, its bandgap is still too large for visible light response, and many methodssuch as doping with metal ions, preparing solid solutions and combining with various narrow bandgap

Figure 1. (a) Band gap measurement of synthesized graphene oxides (GO). (b) AFM image of modified GO. (c)photocatalytic performances of GOs and (d) photocatalytic CO2 reduction mechanism on graphene oxide [29].

SESSION 1D : Nanoelectronics - I


21

semiconductors are the vital approaches to make GO visible light active. In this work, we have developed a seriesof GO-based potent photo-catalyst with copper nanoparticles and MoS2 metal sulfide to achieve a substantialhigh efficiency under visible light. The choice of metal nanoparticles, metal sulfide as a co-catalyst to improvethe photoreduction efficiency of GO is due to their earth abundance, low cost and moderately large workfunction of Cu as compared with GO. However, to the best of our knowledge, it is expected that the Schottkyjunction between those co-catalyst and GO in GO-based composite accelerates the separation ofphotogenerated electron-hole pairs and consequently, improves the photocatalytic activity. Recently, in thephotocatalytic CO2 reduction to solar fuel generation, selective product formation has been one of the mostimportant issues.

In this work, a composite photocatalysts were made from wide-bandgap GO and metal nanoparticles and metalsulfide with narrow size distribution. The redox potential has been tuned using the different composition ratiosof the co-catalyst/GO. We expect to achieve highly selective and efficient production of solar fuels with differentco-catalyst composition in the GO-based composite. Typical one-pot microwave and hydrothermal synthesisprocesses for Cu/GO and MoS2/GO hybrid are presented schematically in Figure 2. In the present study, a seriesof Cu-NPs decorated GO (Cu/GO) composites with different Cu nanocrystal concentrations were synthesized viaa single pot microwave method. The synthesized Cu-NPs modified GOs are denoted as Cu/GO-1(5 wt% Cu),Cu/GO-2 (10 wt% Cu) and Cu/GO-3 (15 wt% Cu), with EDX measured Cu loading of 4.12, 9.52 and 15.16 wt %,respectively. In our experiments, we have synthesized MoS2/GO composites nanostructure by adjusting thedifferent temperature in the one-pot hydrothermal process. The obtained various MoS2/GO composites denotedas MoS2/GO-180, MoS2/GO-200 and MoS2/GO-220 according to the reaction temperature 180, 200 and 220 Crespectively.

The phase structures of the Cu/GOs hybrids and MoS2/GO were examined by X-ray diffraction (XRD)measurement. Figure 3(a) compares the XRD patterns of pristine GO and Cu/GO hybrids in the range of 5

o-70

o

(2). The observed increase d-spacing of GO sheets is due to the presence of abundant oxygen-moieties onboth sides of the graphene sheet causing an atomic-scale roughness on the graphene surface. As shown inFigure 3(a), the Cu/GO hybrids show peaks at around 42.88

othat corresponds to the metallic copper (111)

without any sign of copper oxides signature, indicating that Cu ions were thermally reduced during themicrowave process. In contrast, the Cu/GO hybrids characteristic (002) peak moves to slightly higher diffractionangle at 12.6

o, which is mainly attributed to partial modification of pristine GO during microwave treatment.

Additionally, the average crystalline

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