Photocatalytic Nitrobenzene Reduction and Proton Conduction Study by a Rh–As–POM Assembly System

The development of a novel and stable functional material for photocatalytic organic transformation and proton conduction is of great research significance in the manufacture of crucial drug intermediates and proton-exchange membrane fuel cells. In this study, we employed Na₂MoO₄, NaAsO₂, and RhCl₃ to construct a Rh-containing arsenomolybdate Na₁₆(H₃O)₄[H₂N(CH₃)₂]₂[As₁₂Mo₃₁O₁₂₉Rh₄(OH)₂(H₂O)]·27H₂O (1). The detailed crystallographic analysis determined that compound 1 has a symmetrical structure consisting of two identical {As₆Mo₁₅Rh₂} clusters bridged by a Mo^VI center through Rh and As from each {As₆Mo₁₅Rh₂} group, which was further comprehensively characterized by common spectroscopic methods, encompassing X-ray photoelectron spectroscopy, powder X-ray diffraction, thermogravimetric analysis, and elemental analysis. The systematic impedance spectroscopy revealed that compound 1 not only displays excellent proton conductivity but also retains structural integrity after exposure to different temperature and humidity conditions. Additionally, the high activity and robustness of compound 1 in the photosynthetic aniline were verified after 6 h of visible-light irradiation in a N₂ environment.