CoNi Bimetal Cocatalyst Modifying a Hierarchical ZnIn₂S₄ Nanosheet-Based Microsphere Noble-Metal-Free Photocatalyst for Efficient Visible-Light-Driven Photocatalytic Hydrogen Production

Abstract

Investigating noble-metal-free and earth-abundant cocatalysts has emerged as a promising and challenging issue for improving the photocatalytic hydrogen production efficiency. In this work, a novel CoNi-ZnIn2S4 (CoNi-ZIS) photocatalyst composed of ZnIn2S4 (ZIS) nanosheets (2D) and CoNi bimetal nanosheets (2D) has been designed and fabricated via a simple hydrothermal and chemical reduction process. The detailed characterization results suggest that the introduction of CoNi bimetal is the major driving factor for the improved photocatalytic performance of CoNi-ZIS photocatalyst, which can accelerate the charge migration and inhibit the photoinduced charge carrier (electrons and holes) recombination. The photocatalytic hydrogen production rate of CoNi-ZIS prepared under the optimized condition reaches 100.1 μmol·h–1 irradiated by visible light (λ > 420 nm) in the 0.1 M ascorbic acid (AA), which is approximately 4.3 times higher than that of ZIS. In addition, the potential mechanism over boosted photocatalytic activity was presented according to the characterization results. This study not only develops a specific photocatalyst with an outstanding H2 production property but also provides a favorable inspiration for designing efficient ZnIn2S4-based photocatalyst systems.