[In situ FTIR spectroscopy studies of HCOOH oxidation on surface alloy electrocatalysts].

ABSTRACT

Electrocatalytic properties of three electrodes for formic acid oxidation were studied by using electrochemical in situ FTIR spectroscopy and cyclic voltammetry in this paper. It is demonstrated that the electrocatalytical mechanism of formic acid oxidation on platinum-dispersed carbon(Pt/GC) is similar to that on massive platinum, which involves two paths, i.e. one way through active intermediate and the other through poison intermediate to CO2. The Pt/GC exhibits higher catalytivity than pure platinum. The electrode of Pt/GC modified by Sb (Sb-Pt/GC) was also prepared in the work. It was observed that the onset potential (Ei) for formic acid oxidation on Sb-Pt/GC was shift negatively for 0.20 V. The peak potential (Ep) was observed to shifted negatively to 0.34 V and the value of oxidation current (jp) was enhanced nearly 7.28 times. Similar results were also observed on surface alloy/GC prepared. In this case, Ei and Ep were -0.12 and 0.32 V, respectively, jp was enhanced about 8.15 times, and FWHM (full width at half maximum) was 0.50 V. It is indicated that Sb-Pt/GC and surface alloy/GC can not only effectively restrain the formation of poison intermediate CO, but also significantly increase the electrocatalytic activities for oxidation of active intermediates.