A hierarchical hollow Pt@H-UiO-66-NH2/CdS ternary catalyst for efficient visible light prompted photocatalysis

Abstract

Metal–organic frameworks (MOFs) have great potential for producing photoelectrocatalyzed hydrogen and degrading pollutants, owing to several factors such as high porosity and tunable semiconductor-like properties. Wide band gaps, which restrict their use to only UV light induced reactions, and low efficiencies for the separation of photogenerated charge carriers (electrons and holes) pose significant challenges to the widespread applications of MOFs. In this study, a hierarchical hollow Pt@H-UiO-66-NH₂/CdS ternary catalyst was designed and synthesized. The immobilized CdS nanoparticles (NPs) in this catalyst endow the MOF H-UiO-66-NH₂ with high visible light absorption ability and the Pt NPs serve as electron sinks to improve charge carrier separation. Furthermore, the hierarchical hollow structure of H-UiO-66-NH₂ in the composite contributes to boosting light absorption and shortening the distance for charge transfer. As a proof of principle, Pt@H-UiO-66-NH₂/CdS catalyzes methylene blue (MB) degradation with a high rate constant of 1.025 × 10⁻² and hydrogen production with a rate of 12 810 μmol g⁻¹ h⁻¹, the latter of which is about 2.3, 11.7 and 173 times higher than those of Pt@UiO-66-NH₂/CdS, H-UiO-66-NH₂/CdS and Pt@H-UiO-66-NH₂, respectively.