Improved H2 production of ZnO@ZnS nanorod-decorated Ni foam immobilized photocatalysts

ZnO@ZnS nanorod-decorated Ni foam was prepared as a self-supported photocatalyst for hydrogen generation through a two-step method, including the formation of the ZnO nanorod core by a hydrothermal method, and the fabrication of the ZnS shell by a sulfidation method. The impact of the ZnS shell thickness was studied, including the influence on the optical properties, surface wettability, separation of photoexcited charge carriers, and photocatalytic hydrogen generation performance. Formation of the core-shell ZnO@ZnS structure and the incorporation of the conductive Ni foam substrate can enhance the separation of photoexcited carriers of the immobilized photocatalyst. The formation of ZnO@ZnS nanorods on the Ni foam resulted in a change in the surface from hydrophobic to superhydrophilic. The porous texture of the Ni foam facilitates the effective contact between the sacrificial agent and the immobilized photocatalyst. The ZnO@ZnS/Ni foam photocatalyst that was synthesized using a sulfidation time of 4 h, (namely, NZS4), exhibited H-2 generation activity of 5860 mmol g(-1) h(-1), which is approximately three-fold that of the ZnO/Ni foam photocatalyst (named NZ). After being reused for three cycles, with a simple washing between cycles, the NZS4 photocatalyst retained 90% of its hydrogen generation activity. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

The ZnO@ZnS nanorod-decorated Ni foam photocatalyst showed enhanced photocatalytic activity for hydrogen generation compared to the ZnO/Ni foam counterpart. The incorporation of the ZnS shell and the conductive Ni foam substrate facilitated the separation of photoexcited charge carriers. The porous texture of the Ni foam promoted effective contact between the sacrificial agent and the immobilized photocatalyst, leading to improved hydrogen generation performance.