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

The C[sbnd]C 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 C[sbnd]C 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 C[sbnd]C bonds, whereas Sn promotes the further oxidation of ethanol fragments. DFT (density functional theory) calculations indicate the activation barriers of the C[sbnd]H bond cleavage in CH₃CH₂OH, CH₃CHOH, CH₃CHO, CH₃CO, CH₂CO and the C[sbnd]C 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.