Multi-mode photocatalytic degradation and photocatalytic hydrogen evolution of honeycomb-like three-dimensionally ordered macroporous composite Ag/ZrO2

A three-dimensionally ordered macroporous (3DOM) composite, 3DOM Ag/ZrO2, was prepared by polystyrene (PS) colloidal spheres as a template, combined with the one-step method of vacuum impregnation. The composition, crystalline structure, morphology and surface physicochemical properties were characterized by ICP-AES, XRD, UV-Vis/DRS, XPS, SEM and N2 adsorption–desorption measurements. The results showed that the 3DOM Ag/ZrO2 crystal type was mainly the tetragonal ZrO2 phase, and Ag was present in the form of metallic silver, which resulted in strong absorption in the visible region due to the effect of surface plasmon absorption (SPA). The composite exhibited a honeycomb-like, three-dimensionally ordered macroporous structure that was permeable, open, arranged in order, with holes closely connected with each other, which was a good reproduction of the PS crystal template. The photocatalytic activity of 3DOM Ag/ZrO2 was investigated using Congo red as the model molecule. Compared to ZrO2, P25 and Ag/ZrO2, 3DOM Ag/ZrO2 exhibited better photocatalytic activity under multi-modes including UV, visible light, simulated solar light and microwave-assisted irradiation. Moreover, the 3DOM Ag/ZrO2 composite had a positive effect on the degradation of different types of organic pollutants under UV light. In addition, during the study of photocatalytic hydrogen production, the hydrogen yield of the 3DOM Ag/ZrO2 composite was 18 times that of commercial P25, which also showed excellent photocatalytic activity.