Effect of the Sn(II)/Sn(IV) Redox Couple on the Activity of PtSn/C for Ethanol Electro-oxidation

The PtSn/C-Ni catalyst was prepared by adding Ni(NO3)2 in the reduction process of SnCl2 and H2PtCl6 with ethylene glycol. The coexistence of the Sn(II)/Sn(IV) redox couple was detected in the catalyst by temperature-programmed reduction experiments. Linear sweep voltammetry, single cell test, and CO stripping voltammetry experiments show that the ethanol electro-oxidation activity and CO tolerance can be obviously enhanced by increasing the Sn(II)/Sn(IV) ratio in the catalyst. The reason might be attributed to that the Sn(II)/Sn(IV) redox couple accelerates the transfer rate of (OH)ads and then promotes the consequent oxidation of CO-like intermediates that are produced in the ethanol electro-oxidation process on the surface of Pt.