Noble-metal-free MOF derived hollow CdS/TiO_2 decorated with NiS cocatalyst for efficient photocatalytic hydrogen evolution

摘要

Noble-metal-free hollow NiS/CdS/TiO2 (NS/CT) nanohybrid photocatalyst was prepared by a facile hydrolysis combining sulfidation process using metal-organic framework (MOF) as a template. The as-prepared composites were characterized by SEM, TEM, XRD, XPS, UV-vis, and photoelectrochemical techniques. It is found that NS/CT composites with porous hollow structure show significantly enhanced photocatalytic efficiency compare to TiO2, or CdS/TiO2, or even Pt decorated CdS/TiO2 photocatalysts, for hydrogen evolution from water upon visible light irradiation. Significantly, NS/CT composite with optimum amount of 30% CdS and 0.3% NiS exhibits the highest photoactivity, with H-2 production rate of 2149.15 mu mol.g(-l).h(-1), which is 23.9 and 2.3 times higher than that of the pure CdS particles and the CdS/TiO2 nanocomposites, respectively. The superiority of the composites arises from the synergistic effect of the heterojunction for rapid charge separation and the NiS cocatalyst for accelerated surface redox reaction.