Support induced charge transfer effects on electrochemical characteristics of Pt nanoparticle electrocatalysts

The electrokinetic properties of Pt nanoparticles supported on Carbon (Pt/C) and Boron Carbide-Graphite composite (Pt/BC) are compared over a wide potential range. The influence of the support on the electronic state of Pt was investigated via in-situ X-ray Absorption Spectroscopy. Pt d-band filling...

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Bibliographic Details
Published in:Journal of electroanalytical chemistry (Lausanne, Switzerland) Switzerland), 2018-06, Vol.819, p.163-170
Main Authors: Jackson, Colleen, Smith, Graham T., Markiewicz, Matthew, Inwood, David W., Leach, Andrew S., Whalley, Penny S., Kucernak, Anthony R., Russell, Andrea E., Kramer, Denis, Levecque, Pieter B.J.
Format: Article
Language:English
Subjects:
Boron carbide
Catalysis
Catalysts
Charge transfer
Charged particles
Electric double layer
Electrocatalysts
Electrodes
Electrokinetics
Electron states
Hydrogen oxidation
Mass transit
Mass transport
Metal-support interaction
Nanoparticles
Oxidation
Platinum
Spectrum analysis
X-ray absorption spectroscopy
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Summary:The electrokinetic properties of Pt nanoparticles supported on Carbon (Pt/C) and Boron Carbide-Graphite composite (Pt/BC) are compared over a wide potential range. The influence of the support on the electronic state of Pt was investigated via in-situ X-ray Absorption Spectroscopy. Pt d-band filling, determined from XANES white line analysis, was lower and nearly constant between 0.4 and 0.95V vs. RHE for Pt/BC, indicating more positively charged particles in the double layer region and a delay in the onset of oxide formation by about 0.2V compared to the Pt/C catalyst, which showed a marked increase in d-band vacancies above 0.8V vs. RHE. Moreover, Δμ analysis of the XANES data indicated a lack of sub-surface oxygen for the Pt/BC catalyst compared to the Pt/C catalyst above 0.9V vs. RHE. Additional anion adsorption on the Pt/BC in the double layer region, detected by CO displacement, was also confirmed by XANES analysis of the d-band occupancy. The H2 oxidation activities of electrodes with low catalyst loadings were assessed under high mass transport conditions using the floating electrode methodology. The metal-support interaction between the Pt and BC support improved the maximum hydrogen oxidation current density by 1.4 times when compared to Pt/C.
ISSN:1572-6657
1873-2569
DOI:10.1016/j.jelechem.2017.10.010