3DOM SrTiO3-TiO2 composite material modified by CQDs with up-conversion characteristics: Enhanced photocatalytic degradation and photolysis of water for hydrogen production

Abstract

Semiconductor photocatalysis is considered as an effective technology to ease the global energy shortage, designing efficient photocatalysts with enhanced light absorption, carrier separation and surface reaction is still one of the main strategies to solve its practical application. In this paper, the structure of the synthesized material was controlled by regular polystyrene (PS) colloidal spheres as templates, and the 3DOM SrTiO3-TiO2 composite modified by carbon quantum dots (CQDs) with three-dimensional ordered macroporous structure was prepared. In this composite, CQDs with up-conversion characteristics are used as photosensitizers to expand light absorption. The combination of SrTiO3 and TiO2 enhances the separation efficiency of charges, and the three-dimensional ordered macropore structure reduces the resistance of substances entering the catalyst, further improving the catalytic performance of the material. Under the irradiation of xenon lamp, the hydrogen evolution of the prepared CQDs/3DOM SrTiO3-TiO2 composite reached 578.95 μmol·g−1 after 8 h of photolysis, which is 14.5 times that of the monomer TiO2. In addition, with Rhodamine B (RhB) as the model molecule, the photocatalytic degradation activity of CQDs/3DOM SrTiO3-TiO2 was significantly better than that of other contrast systems under the experimental conditions of multimode photocatalytic degradation, showing enhanced photocatalytic degradation and hydrogen production from water photolysis. This study provides a feasible method for preparing three-dimensional ordered macroporous materials with excellent photocatalytic properties.