50. Photoelectrocatalytic synthesis of aromatic azo compounds over porous nanoarrays of bismuth vanadate

Luo, L.,Liu, Y.,Chen, W.,Xue, X.,Xu, S.-M.,Li, M.,Zhou, H.,Ma, L.,Xu, M.,Kong, X.,Shao, M.,Li, Z.*,Duan, H.*
Chem Catalysis 2022, 3(1), 100472.
DOI: 10.1016/j.checat.2022.11.011

The photoelectrocatalytic (PEC) strategy is increasingly showing its capability to drive chemistry besides water splitting, with successful attempts being made recently on organic reactions, but it has never been explored for aromatic azo compound synthesis, which is widely used in pharmaceutical and industrial regions. In this work, we report a PEC strategy for azobenzene synthesis over a porous BiVO4 nanoarray photoanode under mild conditions, showing high selectivity, Faradaic efficiency, and stability, as well as broad substrate scope. We reveal that the superior performance of BiVO4 is attributed to its moderate adsorption strength of aniline and suitable valence band position for selective aniline oxidation to azobenzene. Moreover, we designed a PEC system that co-produces azo compounds at bipolar by combining the above anodic PEC reaction with nitrobenzene reductive coupling at the cathode, showing maximum electron economy for value-added azo compound productions.