MoB/MnCdS Schottky heterojunction composites: A novel and noble-metal-free photocatalyst for high-efficiency photocatalytic H production.

The development of efficient and low-cost photocatalysts has always been sought in H production from water cracking. Herein, a series of MoB/MnCdS composites were developed for high-performance photocatalytic H production. MnCdS nanoparticles were deposited on bulk metalloid MoB via a hydrothermal method (as confirmed by morphology tests) to construct a Schottky heterojunction. In the composites, the Fermi levels of MnCdS and MoB were rearranged (as confirmed by ultraviolet photoelectron spectroscopy) and the electrons of MnCdS rapidly migrated to MoB (as confirmed by X-ray photoelectron spectroscopy). Ultimately, the formation of the Schottky heterojunction significantly improved interfacial carrier separation, leading to efficient H production. MoB, which exhibits a Pt-like electronic structure, provided active sites for H evolution in the heterojunction composites. Furthermore, compared with those of MnCdS, the visible-light absorption capacity and H evolution kinetics of the heterojunction composites were also vastly improved. After photocatalytic H production, the performance of all heterojunction composites markedly increased. The performance of the composite with 20 % MoB/MnCdS) was the highest (4146.92 μmol·g·h), which was 11.3 times that of MnCdS (367.56 μmol·g·h). The stability of the composites was further evaluated, and the 20MoB/MnCdS composite lost only 12.8 % of its activity, indicating its excellent photostability. The underlying mechanism of H production over the heterojunction composites was also investigated. This work provides an innovative approach for achieving high-efficiency H production in a sulfide solid solution modified by a metalloid MoB cocatalyst.