Cu2+ Doped Tio2-Sio2 With Photonic Crystal Structure For Synergistic Enhancement Of Photocatalytic Degradation Under Visible Light Irradiation

The development of visible light photocatalysts with the ability to efficiently degrade pollutants is an important measure to solve environmental problems. In this paper, Cu2+ doped TiO2-SiO2 (CTS) with photonic crystal structure composite was successfully synthesized via sol-gel strategy and template method. The prepared materials have abundant pore structure and uniform pore diameter, and the pores were arranged in a periodically hexagonal structure. It showed enhancing synergistic effect of adsorption-photodegradation ability for removing Rhodamine B (RhB). The brilliant adsorption capability of the catalyst is not only due to the addition of silica which can increase surface area that results the increase in adsorption ability, but also related to the rich and ordered porous structure provided by the photonic crystal. The catalyst has a narrow band gap similar to 2.92 eV which exhibits the excellent photocatalytic activity for RhB degradation (>95% at 30 min) under visible light irradiation, and possesses higher photocatalytic reaction apparent rate constants (k) which is 7 folds higher than that of pure TiO2. The excellent photocatalytic performance is attributed to the Cu2+ doping that narrows the band gap, increases light absorption, and promotes charge separation. Besides, the constructed photonic crystal structure not only further enhances charge transport but also provides more surface activity sites for photocatalytic reactions. More importantly, the ordered pore structure-photonic crystal can prolong the interaction time between light and catalyst through the slow photon effect and the porous scattering effect. Eventually, the photocatalytic degradation efficiency of the catalyst was significantly improved by the synergistic effect of the above mechanisms.