Formic acid electrooxidation on Pt@Au surface through spontaneous deposition: activity, mechanism and halide effect

Ranjani Muralidharan, Michael McIntosh, Xiao Li.

Department of Chemistry, University of South Florida, USA

Abstract: 

Platinum modified gold catalysts have a great potential as catalyst for formic acid electrooxidation which occurs in the anode of formic acid fuel cells. The goal of this research is to examine the catalytic activity of the atomic adlayers of platinum spontaneously deposited on gold, explore the reaction mechanism of the electrooxidation process and investigate the effect of haloplatinate solution during the deposition process.  Electrochemical results prove the strong activity of Pt@Au surface with higher oxidation current and lower starting potentials.  In situ SERS with potential control has revealed that formate appearing at lower wavenumbers of 300 cm-1 is the possible intermediate in the catalytic processes on all three Pt@Au surfaces, however with different potential-dependent behaviors. Dramatic effect of the haloplatinate has been observed on the catalytic activities of Pt@Au surfaces.  Generally, Pt@Au surface prepared from chloroplatinate is most active in oxidizing formic acid followed by that from bromoplatinate and iodoplatinate solution. Clearly, the use of different haloplatinate solution affects not only the amount of Pt deposited on the Au surface, but also the surface structure of those deposits.