Photocorrosion suppression of copper sulfide via hybridization with amino-functionalized metal-organic framework for natural sunlight-driven photocatalysis

Natural sunlight-driven photocatalysis has been considered as an energy sustainable strategy for the synthesis of fine chemicals, since natural sunlight is inexhaustible. Copper sulfide (CuS) with broad light absorption holds great promise for natural sunlight utilization, while hole-induced photocorrosion seriously hampers its photoactivity and photostability. Herein, we inhibited the photocorrosion by hybridizing CuS with aminofunctionalized metal-organic framework of NH2-MIL-125(Ti) (NM125) to fabricate a Z-scheme heterojunction. Taking advantage of high binding affinity of amino group and copper ion, CuS nanoparticles (NPs) were in situ anchored on NM125 surface via amino group-assisted coordination. Characterization results suggested the diffusion-controlled charge migration in NM125@CuS(x) hybrids, where photoinduced electrons in conduction band (CB) of NM125 transferred to valence band (VB) of CuS, and then combined here. The Z-scheme charge transport could timely consume the photogenerated holes of CuS, and spatially separated the charge carriers. As a result, the obtained NM125@CuS(x) catalysts were highly efficient and stable in natural sunlight-driven Phillips-Ladenburg reaction in air, providing serial benzimidazoles with excellent yields (90-98%). Such natural sunlight-driven photocatalysis system efficiently utilized natural sunlight to synthesize high-value fine chemicals in open air at mild conditions, which opens up a sustainable avenue for the green development of fine chemical engineering.