Effect of ordering of PtCu3 electrocatalyst structure on the stability for oxygen reduction reaction
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Transcript of Effect of ordering of PtCu3 electrocatalyst structure on the stability for oxygen reduction reaction
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Effect of ordering of PtCu3 electrocatalyst structure on the stability for oxygen reduction reaction
Nejc Hodnik1,2, C. Jeyabharathi1,3, K. Phani3, A. Renik4, M. Bele2, S. Hoevar2, M. Gaberek2 and K. Mayrhofer1
1Max-Planck-Institut fr Eisenforschung GmbH, Dsseldorf, GermanyDepartment of Interface Chemistry and Surface EngineeringElectrocatalysis Group2National Institute of Chemistry, Ljubljana, Slovenia3CSIR-Central Electrochemical Research Institute, Tamil Nadu, India4Joef Stefan Institute, Ljubljana, Slovenia
10thEuropean Symposium on Electrochemical Engineering, Sardinia, Italy /#
Effect of ordering of PtCu3 electrocatalyst structure on the stability for oxygen reduction reactionLike Pt-based nanoparticles on high surface carbon.
Membrane
AnodeCathodeElectrocatalyst requires improvement of performance & stability = cost !Key parameters for expensive catalytic nanoparticlesIntroduction Monolayer concept PtCu3 nanoparticles Microscopy
Intro#
10thEuropean Symposium on Electrochemical Engineering, Sardinia, Italy /#
Effect of ordering of PtCu3 electrocatalyst structure on the stability for oxygen reduction reaction
ESA electrochemical surface areaS/m = [m2Pt/gPt]
S = 4r2m= (4/3)r3 S/m=k*1/rjm mass activityI/m = [A/mgPt]
I = kSce-kEm= (4/3)r3 jk specific activityI/S = [mA/cm2Pt]I = kSce-kES = 4r2Key parameters for expensive catalytic nanoparticlesThe activity:
X
= jm = ESA * jk
Introduction Monolayer concept PtCu3 nanoparticles Microscopy
Intro#
10thEuropean Symposium on Electrochemical Engineering, Sardinia, Italy /#
Effect of ordering of PtCu3 electrocatalyst structure on the stability for oxygen reduction reaction
Core-shell particles have by default larger ESA
Monolayer type ESA = constant = 152 m2/gPtMonolayer concept: Increasing ESA
PtCu
Interestingy, here ESA is particel size independent! Unlike the activity!Introduction Monolayer concept PtCu3 nanoparticles MicroscopySounds much like Pt-monolayer concept of Prof. Adzic group and Pt-skin of Prof. Markovic group. jm = ESA * jk
Intro#
10thEuropean Symposium on Electrochemical Engineering, Sardinia, Italy /#
Effect of ordering of PtCu3 electrocatalyst structure on the stability for oxygen reduction reaction
Potential advantages reached besides high ESA are enhanced specific activity due to altered Pt electrochemical adsorptive properties:
1.Particle size effect2. Shape effect3.Ligand effect4.Strain effect5.Proximity effect6.Nano-confidement effect...
x.Effect od structural ordering
PtCu
Monolayer concept: Increasing jkSounds much like Pt-monolayer concept of Prof. Adzic group and Pt-skin of Prof. Markovic group.Introduction Monolayer concept PtCu3 nanoparticles Microscopy jm = ESA * jk
Intro#
10thEuropean Symposium on Electrochemical Engineering, Sardinia, Italy /#
Effect of ordering of PtCu3 electrocatalyst structure on the stability for oxygen reduction reactionReal model system: PtCu3 nanoparticles on C
0,0250,015
1,001,330,330,671,672,002,33Introduction Monolayer concept PtCu3 nanoparticles Microscopy
jm = ESA * jk
Intro#
10thEuropean Symposium on Electrochemical Engineering, Sardinia, Italy /#
Effect of ordering of PtCu3 electrocatalyst structure on the stability for oxygen reduction reaction
Real model system: PtCu3 nanoparticles on C
Introduction Monolayer concept PtCu3 nanoparticles Microscopy
1. Partially Ordered samples:Annealing 15 min at 750 C followed by 1 hour at 500 C in reductive atmosphere
2. Disordered sample: Heating the ordered sample to 700 C with subsequent quenching in liquid nitrogen
500C disorderorder transition temperature
Both samples are embedded on a graphitic carbon support with identical initial composition, particle dispersion and size distribution, yet with different degrees of structural ordering.
Intro#
10thEuropean Symposium on Electrochemical Engineering, Sardinia, Italy /#
Effect of ordering of PtCu3 electrocatalyst structure on the stability for oxygen reduction reaction
Introduction Monolayer concept PtCu3 nanoparticles MicroscopyPtCu3 nanoparticles dealloying and activityRregardless of the degradation/dealloying treatment, the partially ordered structure contains significantly higher (2030%) specific activity compared to the fully disordered sample.
See Nejc Hodnik, Miran Gaberek,Karl J. J. Mayrhofer et al.,Phys. Chem. Chem. Phys.2014, 16, 13610.See Marjan Bele, Nejc Hodnik and Miran Gaberek et al.,Chem. Comm.2014, :DOI:10.1039/c4cc05637j.
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10thEuropean Symposium on Electrochemical Engineering, Sardinia, Italy /#
Effect of ordering of PtCu3 electrocatalyst structure on the stability for oxygen reduction reactionPlatinum dissolution: PtCu3 nanoparticlesIntroduction Monolayer concept PtCu3 nanoparticles MicroscopyDissolution of Platinum: Limits for the Deployment of Electrochemical Energy Conversion?**Angel A. Topalov and Karl J. J. MayrhoferAngew. Chem. Int. Ed. 2012, 51, 12613 12615
ElectrolytesupplyCounter electrode
Electrolyteoutlet
Reference electrode
Silicon sealing
50-500mN
2mm
Working electrode
Intro#
10thEuropean Symposium on Electrochemical Engineering, Sardinia, Italy /#
Effect of ordering of PtCu3 electrocatalyst structure on the stability for oxygen reduction reaction
Platinum dissolution: PtCu3 nanoparticlesIntroduction Monolayer concept PtCu3 nanoparticles MicroscopyHow to decide if one has an opportunity to choose between high ESA and low SA or low ESA and high SA?New Insight into Platinum Dissolution from Nanoparticulate Platinum-Based Electrocatalysts Using Highly Sensitive In Situ Concentration MeasurementsJovanovic P., Hodnik N. and M Gaberscek. CHEMCATCHEM, 2014, vol. 6, i. 2, pp. 449-453.
Intro#
10thEuropean Symposium on Electrochemical Engineering, Sardinia, Italy /#
Effect of ordering of PtCu3 electrocatalyst structure on the stability for oxygen reduction reaction
20 nmIntroduction Monolayer concept PtCu3 nanoparticles MicroscopyIdentical location TEM of PtCu3 nanoparticles
Intro#
10thEuropean Symposium on Electrochemical Engineering, Sardinia, Italy /#
Effect of ordering of PtCu3 electrocatalyst structure on the stability for oxygen reduction reaction- dealloying: 500 + 6500 cycles in 0,1 M HClO4Introduction Monolayer concept PtCu3 nanoparticles MicroscopyIdentical location SEM of PtCu3 nanoparticles0.6 1.2 V
20 nm
Intro#
10thEuropean Symposium on Electrochemical Engineering, Sardinia, Italy /#
Effect of ordering of PtCu3 electrocatalyst structure on the stability for oxygen reduction reaction
First try with in-situ electrochemical TEMDealloying of PtCu3 with cycling:- pores formation- beam induced (radiolysis) dynamic nanoscale Cu precipitationIntroduction Monolayer concept PtCu3 nanoparticles Microscopy100 nm
Protochips Poseidon 500
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10thEuropean Symposium on Electrochemical Engineering, Sardinia, Italy /#
Effect of ordering of PtCu3 electrocatalyst structure on the stability for oxygen reduction reaction
Thank you for your attention!Introduction Monolayer concept PtCu3 nanoparticles Microscopy40 nm
Intro#
10thEuropean Symposium on Electrochemical Engineering, Sardinia, Italy /#
Effect of ordering of PtCu3 electrocatalyst structure on the stability for oxygen reduction reaction
Introduction Monolayer concept PtCu3 nanoparticles Microscopy100 nm
Intro#
10thEuropean Symposium on Electrochemical Engineering, Sardinia, Italy /#
Effect of ordering of PtCu3 electrocatalyst structure on the stability for oxygen reduction reaction
M. K. Debe, Nature, 2012, 486, 43-51.
Introduction Monolayer concept PtCu3 nanoparticles MicroscopyReal PtCu3 nanoparticles catalyst activity
Intro#
10thEuropean Symposium on Electrochemical Engineering, Sardinia, Italy /#
Effect of ordering of PtCu3 electrocatalyst structure on the stability for oxygen reduction reaction
Pt-Cu -> Cu2+ (0,74V)
Introduction Monolayer concept PtCu3 nanoparticles Microscopy
Intro#
10thEuropean Symposium on Electrochemical Engineering, Sardinia, Italy /#
Effect of ordering of PtCu3 electrocatalyst structure on the stability for oxygen reduction reaction- dealloying: 500 + 6500 cycles in 0,1 M HClO420 nm
Introduction Monolayer concept PtCu3 nanoparticles MicroscopyIdentical location SEM of PtCu3 nanoparticles20 nm
18zero cycles5,000 cycles50,000 cycles500 cycles0.6 1.2 V
Intro#
10thEuropean Symposium on Electrochemical Engineering, Sardinia, Italy /#