ZnCo2S4/Zn0.2Cd0.8 S Z-scheme heterojunction: Efficient photocatalytic H2 evolution coupling selective oxidation of benzyl alcohol

The Z-scheme heterojunction photocatalysts possess excellent photocatalytic activity benefitting from their properly matched edge potentials. In this work, ZnCo2S4 nano -particles are anchored on Zn0.2Cd0.8S solid solution nanowires and assembled into binary ZnCo2S4/Zn0.2Cd0.8S nanocomposites. The as-synthesized ZnCo2S4/Zn0.2Cd0.8S nano -composites act as bifunctional photocatalysts, which can be used for high-performance H2 production coupling synthesis of high-value-added benzaldehyde in low concentration benzyl alcohol solution. Under visible light irradiation, 20%-ZnCo2S4/Zn0.2Cd0.8S nano -composite shows the highest H2 evolution rate of 23.02 mmol g-1 h-1 in the first photo -catalytic cycle, which is 395.0 and 526.7 times higher than that of Zn0.2Cd0.8S and ZnCo2S4 under the same conditions. Eventually, after six-time cycles, the conversion rate and selectivity of benzyl alcohol oxidation to benzaldehyde are 54.3% and 92.2%, respectively. The enhancement of photocatalytic performance is mainly attributed to the Z-scheme heterojunction between ZnCo2S4 and Zn0.2Cd0.8S, which promote the separation and transfer of photogenerated charge carriers. This work provides strong support for the rational design of Z-scheme nano-heterojunction of highly efficient photocatalytic appli-cation in H2 evolution and fine chemicals production.(c) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

In this work, ZnCo2S4/Zn0.2Cd0.8S nanocomposites were synthesized and demonstrated to be bifunctional photocatalysts for efficient H2 production and synthesis of high-value-added benzaldehyde. The enhanced photocatalytic performance is attributed to the Z-scheme heterojunction between ZnCo2S4 and Zn0.2Cd0.8S, which promotes the separation and transfer of photogenerated charge carriers.