Carboxyl group enhanced CO tolerant GO supported Pt catalysts: DFT and electrochemical analysis

S. Sharma, M. N. Groves, J. Fennell, Navneet Soin, S. L. Horswell, C. Malardier-Jugroot

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Abstract

The effect of residual oxygen species in as-prepared Pt nanoparticle on partially reduced graphene oxide (Pt/PRGO) and partially reduced carboxylated-GO (Pt/PR(GO-COOH)) supports was investigated using electrochemical CO stripping and density functional theory (DFT) analysis. Pt/PRGO and Pt/PR(GO-COOH) revealed a clear negative shift in CO-stripping onset potential compared to commercial Pt/carbon black. DFT analysis confirmed that the presence of a -COOH group provides the most resistance for CO adsorption. This CO-Pt binding energy is significantly lower than that observed in the presence of an OH group, which is the most abundant oxygen group in carbon supports. The Pt-CO dissociation energies (on a 42-atom graphene sheet) in the presence of various oxygen groups, in descending order, were OH > C=O ≈ C-O-C > COOH. Although single-bonded carbon-oxygen groups (-OH and C-O-C) are more abundant on the GO basal plane and play an important role in Pt nanoparticle nucleation and distribution on graphene sheets, the double-bonded carbon-oxygen (C=O and COOH) groups are more abundant residual species post Pt nanoparticle growth and play a vital role in enhancing CO tolerance.

Original languageEnglish
Pages (from-to)6142-6151
Number of pages10
JournalChemistry of Materials
Volume26
Issue number21
DOIs
Publication statusPublished - 11 Nov 2014

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Sharma, S., Groves, M. N., Fennell, J., Soin, N., Horswell, S. L., & Malardier-Jugroot, C. (2014). Carboxyl group enhanced CO tolerant GO supported Pt catalysts: DFT and electrochemical analysis. Chemistry of Materials, 26(21), 6142-6151. https://doi.org/10.1021/cm502447s