Growth of Zn0.5Cd0.5S/α-Ni(OH)2 heterojunction by a facile hydrothermal transformation efficiently boosting photocatalytic hydrogen production

Abstract

Improving the efficiency of charge separation is an important aspect in photocatalysis. In this work, the hybrid nanostructure of α-Ni(OH)₂/Zn_0.5Cd_0.5S has been prepared by a simple two-step method for the first time. Here, designed/constructed with α-Ni(OH)₂ over Zn–Cd–S, the catalyst efficiently boosts hydrogen evolution in photocatalytic hydrogen production. With a 25% content of α-Ni(OH)₂ in the ZSN25 composite under visible light (λ ≥ 420 nm) irradiation, remarkable hydrogen production of 22.45 mmol g⁻¹ h⁻¹ has been achieved. In addition, we found that the activities could be improved by means of controlling the formation of α-Ni(OH)₂ species. The reason is that the interface between α-Ni(OH)₂ and Zn_0.5Cd_0.5S provides a fast charge transfer channel to reduce the recombination of photogenerated carrier. Also, the formation of this interface is largely related to the content of α-Ni(OH)₂. The Tafel slope, EIS and PL spectra support enhanced photocatalytic energy in the α-Ni(OH)₂/Zn_0.5Cd_0.5S charge transfer state and faster hydrogen evolution kinetics. These nanocomposites of Zn_0.5Cd_0.5S modified by α-Ni(OH)₂ are of great significance for renewable hydrogen generation technology.