Coordinatively unsaturated bismuth sites accelerate in-situ hydrogen peroxide electrochemical formation for efficient butanone oxime synthesis
Fan He, Yingnan Liu, Xianyun Peng, Yaqi Chen, Qiang Zheng, Bin Yang, Zhongjian Li, Qiang Zhou, Qinghua Zhang, Jianguo Lü, Lecheng Lei, Gang Wu, Yang Hou
Abstract
Selective electrochemical water oxidation via a 2e− pathway represents a sustainable H2O2 electrosynthesis route. However, the low activity and selectivity due to competing 4e− oxygen evolution and challenges in separating in-situ-generated H2O2 for subsequent reactions. Herein, we develop an unsaturated coordinative bismuth-benzene tricarboxylic acid metal-organic framework using a hetero-linker doping strategy. The catalyst demonstrates enhanced performance in selective H2O2 synthesis, achieving a low overpotential of 0.98 V and high selectivity with a Faradaic efficiency of 79.1%. The accumulated ~6.17 wt.% H2O2 enables an efficient direct conversion of butanone ammoximation to butanone oxime, showing a high conversion rate of 80.2% and a selectivity of 81.1%. Structural characterizations reveal the unsaturated coordination in the central bismuth atoms. These unsaturated coordinative bismuth sites modulate the OH* intermediate adsorption and optimize the free energy of OH* → H2O2, as revealed by in-situ attenuated total reflection Fourier transform infrared spectroscopy and theoretical calculations. This work provides a strategy for rationalizing selective 2e− water oxidation catalysts and advances the industrially valuable reaction for value-added chemicals production. Selective electrochemical water oxidation via a 2e− pathway represents a sustainable H2O2 electrosynthesis route. Here, the authors develop an unsaturated coordinative bismuth-benzene tricarboxylic acid metal-organic framework using a hetero-linker doping strategy for high activity and selectivity.