Selective Ethanol Oxidation Reaction at the Rh-SnO2 Interface.

Abstract

Direct ethanol fuel cells (DEFCs) are regarded as an attractive power source with high energy density, bio-renewability, and convenient storage and transportation. However, the anodic reaction of DEFCs, that is, the ethanol oxidation reaction (EOR), suffers from poor efficiency due to the low selectivity to CO2 (C1 pathway) and high selectivity to CH3 COOH (C2 pathway). In this study, the selective EOR to CO2 can be achieved at the Rh-SnO2 interface in SnO2 -Rh nanosheets (NSs). The optimized catalyst of 0.2SnO2 -Rh NSs/C exhibits excellent alkaline EOR performance with a mass activity of 213.2 mA mgRh -1 and a Faraday efficiency of 72.8% for the C1 pathway, which are 1.7 and 1.9 times higher than those of Rh NSs/C. Mechanism studies indicate that the strong synergy at the Rh-SnO2 interface significantly promotes the breaking of CC bond of C2 H5 OH to form CO2 , and facilitates oxidation of the poisonous intermediates (* CO and * CH3 ) to suppress the deactivation of the catalyst. This work not only provides a highly selective, active, and stable catalyst for the EOR, but also promotes fundamental research for the design of efficient catalysts via interface modification.