Ethanol electro-oxidation on the PdSn-TaN/C catalyst in alkaline media: Making TaN capable of splitting C[sbnd]C bond

Abstract

The CC bond cleavage remains a main challenge for alkaline EOR (ethanol oxidation reaction). In this work, we report an efficient PdSn-TaN/C electrocatalyst to split the CC bonds in ethanol. Structurally, a series of characterization results confirm the presence of the low-coordinated Pd sites on the PdSn-TaN/C interface. The PdSn-TaN/C catalyst exhibits very high activity (almost 26.9 times of commercial Pd/C), good durability and high selectivity to CO2 (20.5%) towards alkaline EOR. Specifically, in-situ ATR-SEIRAS (Attenuated total reflection-surface enhanced infrared absorption spectroscopy) results indicate that TaN facilitates the cleavage of CC bonds, whereas Sn promotes the further oxidation of ethanol fragments. DFT (density functional theory) calculations indicate the activation barriers of the CH bond cleavage in CH3CH2OH, CH3CHOH, CH3CHO, CH3CO, CH2CO and the CC bond cleavage in CH3CO, CH2CO, CHCO are reduced evidently and the removal of adsorbed CH3CO and CO becomes easier on the PdSn-TaN/C catalyst surface.