Enhanced photoelectrochemical performance of ZnO/NiFe-layered double hydroxide for water splitting: Experimental and photo-assisted density functional theory calculations

Hydrogen production technologies have attracted considerable attention with the increasing demand for renewable energy. Among them, the combined action of water electrolysis and solar energy has emerged. In this study, a hydrangea ZnO/NiFe-layered double hydroxide (LDH) heterojunction was synthesized using the two-step hydrothermal method. The resulting ZnO/NiFe-LDH improved the range and intensity of light response, thus meeting the requirement of electrocatalysis and photocatalysis in theory. Moreover, ZnO/NiFe-LDH demonstrated excellent activity in the electrochemical performance test in the presence of light. When used as a water splitting catalyst in a full cell, the cell voltage was 1.632 V, and Faradic efficiency was 99.1%. Moreover, from the in situ Raman and theoretical calculation results, it is possible to conclude that the synthesized ZnO/NiFe-LDH has the property of absorbing light energy, and the introduction of light energy can optimize the bandgap structure of the material and enhance the adsorption capacity of the system, thus significantly reducing the energy required for water splitting reaction. In sum, this study introduced a composition strategy for LDH heterojunction materials and presented a theoretical and experimental investigation of the light influence on the material structure and electrochemical reaction. Furthermore, it is believed that an important future direction of hydrogen production is photo-assisted water splitting.