Highly active Ptx(SnO2)100-x/C catalysts towards the hydrogen oxidation reaction and tolerant to the presence of carbon monoxide

Pt x (SnO 2 ) 100-x /C materials consist of 1.5 to 2.5 nm nanoparticles deposited on a carbon support and decorated by SnO 2 . Pt and Sn are slightly alloyed (5 % to 8 %) in nanoparticles. From XPS study the Sn 3d peaks present a shift towards lower binding energy values, indicating clearly an electron transfer from Pt(PtSn) towards SnO 2 (electronic metal support interaction − EMSI). The incorporation of SnO 2 into Pt enhances the catalytic activity towards the HOR at 0.02 V vs . RHE. The mass activity doubles, increasing from 147 m A m g P t - 1 for Pt/C to 286 m A m g P t - 1 for Pt 50 (SnO 2 ) 50 /C, while the specific activity increases fourfold, from 0.33 mA c m P t - 2 to 1.33 m A c m P t - 2 . These enhancements are attributed to EMSI. Pt x (SnO 2 ) 100-x /C catalysts exhibit lower onset potentials for CO ads removal compared to Pt/C, both in the absence and presence of hydrogen. The high rate of CO removal is attributed to the bifunctional mechanism, while the shift of the CO ads oxidation onset potential towards lower values from a ligand effect. At 60 °C, all catalysts show activity for the HOR from 0.05 V vs . RHE in the presence of CO. Among them, Pt 50 (SnO 2 ) 50 /C demonstrates the highest HOR activity and the greatest CO tolerance.