Photocatalytic CO2 Reduction Over Ni-Modified Cd1−xZnxS-Based Photocatalysts: Effect of Phase Composition of Photocatalyst and Reaction Media on Reduction Rate and Product Distribution

Abstract

Two types of nickel-modified Cd1−xZnxS-based photocatalysts, CdxZn1−xNiySy+1 (mol% Ni = 0.05–0.5; x = 0.8) and yNiS/CdxZn1−xS (mol% Ni = 0.1–1.0; x = 0.8), were prepared via a simple two-stage technique. The samples were characterized by XRD, UV–vis spectroscopy, and XPS techniques. The activity of the synthesized photocatalysts were tested in the gas-phase photocatalytic reduction of CO2 under visible light (λ = 450 nm). It has been shown that both CdxZn1−xNiySy+1 and yNiS/CdxZn1−xS samples with ultra-low content of nickel sulfide have improved activity in the carbon dioxide reduction in comparison to bare CdxZn1−xS solid solutions. Also, it has been demonstrated that the addition of the reducing agent—hydrogen—into the system does not lead to a positive effect: the rate of CO2 reduction either remains unchanged or decreases.