Interfacial Electron Engineering of PdSn-NbN/C for Highly Efficient Cleavage of the C-C Bonds in Alkaline Ethanol Electrooxidation

The splitting of the C-C bonds of ethanol remains a key issue to be addressed, despite tremendous efforts made over the past several decades. This study highlights the enhancement mechanism of inexpensive NbN-modified Pd1Sn3-NbN/C towards the C-C bonds cleavage for alkaline ethanol oxidation reaction (EOR). The optimal Pd1Sn3-NbN/C delivers a catalytic activity up to 43.5 times higher than that of commercial Pd/C and high carbonate selectivity (20.5%) toward alkaline EOR. Most impressively, the Pd1Sn3-NbN/C presents good durability even after 25 200 s of chronoamperometric testing. The enhanced catalytic performance is mainly due to the interfacial interaction between PdSn and NbN, demonstrated by multiple structural characterization results. In addition, in situ ATR-SEIRAS (Attenuated total reflection-surface enhanced infrared absorption spectroscopy) results suggest that NbN facilitates the C-C bonds cleavage towards the alkaline EOR, followed by the enhanced OH adsorption to promote the subsequent oxidation of C1 intermediates after doping Sn. DFT (density functional theory) calculations indicate that the activation barriers of the C-H bond cleavage in CH3CH2OH, CH3CHOH, CH3CHO, CH3CO, CH2CO, and the C-C bond cleavage in CH3CO, CH2CO, CHCO are evidently reduced and the removal of adsorbed CH3CO and CO becomes easier on the PdSn-NbN/C catalyst surface. The C-C bond cleavage remains a main challenge for EOR (ethanol oxidation reaction). Palladium-modified transition metal nitrides (NbN) are investigated as electrochemical EOR catalysts. Structurally, characterization results confirm the presence of the PdSn-NbN/C interface. Combined in situ ATR-SEIRAS and density functional theory (DFT) results demonstrate PdSn-NbN/C as an effective material to split the C-C bonds in ethanol while controlling the reaction pathway of EOR.image