Amorphous CoSx decorated Cd0.5Zn0.5S with a bulk-twinned homojunction for efficient photocatalytic hydrogen evolution

Herein, an efficient CoSx/twinned-Cd0.5Zn0.5S (CoSx/T-CZS) photocatalyst was successfully constructed by an in situ deposition method. Notably, the establishment of the zinc-blende/wurtzite (ZB/WZ) homojunction in T-CZS and the heterojunction between CoSx and T-CZS can facilitate the charge separation in the bulk and surface of T-CZS, simultaneously. As a consequence, T-CZS exhibited much higher activity compared to the zinc blende Cd0.5Zn0.5S (ZB-CZS) and wurtzite Cd0.5Zn0.5S (WZ-CZS) with single-phase. After introducing amorphous CoSx, the H-2 evolution rate of 4 wt% CoSx/T-CZS reached 76.2 mmol h(-1) g(-1) in 20 vol% triethanolamine (TEOA) aqueous solution under 300 W Xe lamp irradiation at 30 degrees C, which was nearly 5.9 times higher than that of pure T-CZS. The excellent activity is mainly attributed to the avoidance of rapid recombination of bulk and surface photogenerated electron-hole pairs through the synergistic effect of the homo-heterojunction structure. In addition, the good optical absorption abilities of CoSx/T-CZS and their photo-electrochemical properties are helpful to improve the reactivity of CoSx/T-CZS. This work provides new ideas for constructing noble metal-free photocatalysts with homo-heterojunction.

Automated summary

An efficient CoSx/T-CZS photocatalyst with zinc-blende/wurtzite homojunction and heterojunction between CoSx and T-CZS was successfully constructed. The introduction of amorphous CoSx significantly improved the H-2 evolution rate of the photocatalyst. This work provides new ideas for constructing noble metal-free photocatalysts with homo-heterojunction.