Catalysis by Cubes
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David M.A. Verbart * , Jim van Mourik ** , Sonja I.R. Castillo Van ’t Hoff Laboratory for Physical and Colloid Chemistry Debye Institute for Nanomaterials Science, Utrecht University, The Netherlands *[email protected], **[email protected] The used hematite cubic colloids. Note the rough surface. The used hematite cubic colloids with silica coating. Note the smooth surface. Silica coated hematite cubes after reaction, with UV light. Note the slightly damaged silica coating. Colloids are particles between 1 and 1000 nm which exist in various shapes and are formed of different materials. [1] Recently, cubic colloids with a hematite (α-Fe 2 O 3 ) core and a silica coating were highlighted due to their remarkable shape and assembly properties. [2,3] Previous research also shows that these cubes can be used as Fenton-like catalyst [4] with the hematite core as the catalytically active site. The Fenton reaction is the catalytic degradation of organic molecules of Fe 2+ and hydrogen peroxide. [5] This degradation is very effective in waste water treatment. [6] Because the Fenton reaction can be sped up by UV light, [7] we investigated the influence of UV light on the catalytic activity. Particularly, is the silica sufficiently porous to let the UV light through the silica coating? Silica coated hematite cubes after reaction, without UV light. Note the severely damaged silica coating. Typical UV-Vis spectra of the methylene blue and hydrogen peroxide mixture with silica coated hematite cubes, under UV illumination. The absorbance decreases over time. References [1] D.H. Everett. Basic Principles of Colloid Science. Royal Society of Chemistry. (1988) [2] L. Rossi, S. Sacanna, W.T.M. Irvine, P.M. Chaikin, D.J. Pine and A.P. Philipse, Soft Matter 7. (2011) [3] J.M. Meijer, F. Hagemans, L. Rossi, D.V. Byelov, S.I.R. Castillo, A. Snigirev, I. Snigereva, A.P. Philipse, A.V. Petukhov, Langmuir , 28, 7631-7638. (2012) [4] C.E. Pompe, Sonja I.R. Castillo, Albert P. Philipse, Poster. [5] Sihoon Lee, Jooyub Oh and Yoonchang Park. Bull. Korean Chem. Soc. Vol 27, no 4, 489. (2006) [6] E. Meyens and J. Baeyens, Journal of Hazardous Materials 98, 33. (2003) [7] E. Brillas, I. Sirés and M.A. Otura. Chem. Rev. 109, 6570-6631. (2009) The degradation of metylene blue is faster when the catalytic cubes are added. This reaction is even faster under influence of UV light. Conclusions • Colloidal hematite cubes, with and without silica coating, are indeed able to act as Fenton-like catalyst to degrade organic molecules with hydrogen peroxide • The catalysis by hematite cubes is sped up by UV light and can be considered as photocatalysis • Silica is sufficiently porous to let UV light through the silica coating • The silica coating is destroyed after a reaction without UV light, but seems better maintained after a reaction with UV light. Outlook More research has to be done on the stability of the silica coating of the cubes. Why is the silica coating destroyed after a reaction without UV light and is it maintained after a reaction with UV light? Acknowledgements First, Sonja Castillo is thanked for her supervision and help. We thank Lisette Pompe, on whose research we could build on. Furthermore, we thank all members of the FCC group for their open attitude, useful help and hospitality. Catalysis by Cubes The influence of UV light
Transcript of Catalysis by Cubes
David M.A. Verbart*, Jim van Mourik**, Sonja I.R. Castillo
Van ’t Hoff Laboratory for Physical and Colloid ChemistryDebye Institute for Nanomaterials Science, Utrecht University, The Netherlands*[email protected], **[email protected]
The used hematite cubic colloids. Note the rough surface.
The used hematite cubic colloids with silica coating. Note the smooth surface.
Silica coated hematite cubes after reaction, with UV light. Note the slightly damaged silica coating.
Colloids are particles between 1 and 1000 nm which exist in various shapes and are formed of different materials.[1]
Recently, cubic colloids with a hematite (α-Fe2O3) core and a silica coating were highlighted due to their remarkable shape and assembly properties.[2,3]
Previous research also shows that these cubes can be used asFenton-like catalyst[4] with the hematite core as the catalytically active site.
The Fenton reaction is the catalytic degradation of organic molecules of Fe2+ and hydrogen peroxide.[5] This degradation is very effective in waste water treatment.[6]
Because the Fenton reaction can be sped up by UV light,[7]
we investigated the influence of UV light on the catalytic activity.Particularly, is the silica sufficiently porous to let the UV light through the silica coating?
Silica coated hematite cubes after reaction, without UV light. Note the severely damaged silica coating.
Typical UV-Vis spectra of the methylene blue and hydrogen peroxide mixture with silica coated hematite cubes, under UV illumination. The absorbance decreases over time.
References[1] D.H. Everett. Basic Principles of Colloid Science. Royal Society of Chemistry. (1988)[2] L. Rossi, S. Sacanna, W.T.M. Irvine, P.M. Chaikin, D.J. Pine and A.P. Philipse, Soft Matter 7. (2011)[3] J.M. Meijer, F. Hagemans, L. Rossi, D.V. Byelov, S.I.R. Castillo, A. Snigirev, I. Snigereva, A.P. Philipse, A.V. Petukhov, Langmuir , 28, 7631-7638. (2012)[4] C.E. Pompe, Sonja I.R. Castillo, Albert P. Philipse, Poster. [5] Sihoon Lee, Jooyub Oh and Yoonchang Park. Bull. Korean Chem. Soc. Vol 27, no 4, 489. (2006)[6] E. Meyens and J. Baeyens, Journal of Hazardous Materials 98, 33. (2003)[7] E. Brillas, I. Sirés and M.A. Otura. Chem. Rev. 109, 6570-6631. (2009)
The degradation of metylene blue is faster when the catalytic cubes are added. This reaction is even faster under influence of UV light.
Conclusions• Colloidal hematite cubes, with and without silica coating, are indeed able to act as Fenton-like catalyst to degrade organic molecules with hydrogen peroxide• The catalysis by hematite cubes is sped up by UV light and can be considered as photocatalysis• Silica is sufficiently porous to let UV light through the silica coating• The silica coating is destroyed after a reaction without UV light, but seems better maintained after a reaction with UV light.
OutlookMore research has to be done on the stability of the silica coating of thecubes. Why is the silica coating destroyed after a reaction without UV light and is it maintained after a reaction with UV light?
AcknowledgementsFirst, Sonja Castillo is thanked for her supervision and help. We thank Lisette Pompe, on whose research we could build on. Furthermore, we thank all members of the FCC group for their open attitude, useful help and hospitality.
Catalysis by CubesThe influence of UV light
