The distinct role of non-noble metal Cu NPs deposition in boosting the overall photocatalytic performance over a ternary Zn-based photocatalyst system

Highlights: • Cu NPs deposition brings about strong visible light absorption and fast separation of the photogenerated carriers. • The synergistic effect between the plasma effect of Cu NPs and single Z-scheme. • The superior photocatalytic performance for hydrogen production, dye decomposition, and Cr(VI)reduction. -- Abstract: Metal nanoparticles (NPs) deposition is an effective strategy to enhance the photocatalytic performance. Here, we developed a non-noble Cu NPs deposition strategy to largely boost the overall photocatalytic performance of a ternary Zn-based composite photocatalyst (ZnTiO₃/Zn₂Ti₃O₈/ZnO, ZTO). The physicochemical properties of copper-deposited ZTO were extensively analyzed by a series of techniques such as XRD, BET, FT-IR, XPS, TEM, PL, and photoelectrochemical tests. And the free radical and light absorption properties of copper-deposited ZTO were examined by ESR and UV–vis DRS, respectively. The photocatalytic performance for hexavalent chromium reduction removal, dye decomposition, and water splitting for hydrogen production without noble metal cocatalyst were investigated. The results show that with suitable Cu content (3%~ 4.7%), the Cu-ZTO samples showed high activity for Cr(VI) reduction (3.2 times reduction rate of ZTO), dye decomposition(5.3 times degradation rate of ZTO), and hydrogen generation (19 times of the H₂ production rate of ZTO). The synergistic effect between the plasma effect of Cu NPs and single Z-scheme mechanism over ternary ZTO results in a strong visible light absorption and fast separation of photogenerated electrons and holes. Thus, a superior photocatalytic performance was obtained over this novel Cu-ZTO photocatalyst system.