Immobilization laccase on heterophase TiO2 microsphere as a photo-enzyme integrated catalyst for emerging contaminants degradation under visible light

Abstract

The successful combination of enzymes and photocatalysts in one pot is an elegant approach for the reactions with high efficiency. This combination usually requires both enzymes and photocatalysts with reasonable activity under the same condition. Herein, a photo-enzyme integrated catalyst by immobilizing laccase on clustered porous TiO2 heterophase junction (HPJs) microsphere (denoted as mTiO2-CVs) is synthesized for the first time. The TiO2 microsphere with ordered regular radial structure and controllable heterophase junction (anatase/rutile) composition is prepared by a pressure-driven hydrothermal assembly method. The ratio of rutile and anatase phase of mTiO2-CVs can be controlled by adjusting the amount of hydrochloric acid in the preparing process. The characterization results of mTiO2-CVs prove that the mTiO2-CVs has regular morphology, uniform mesoporous structure, larger specific surface area and narrower band gap, and can realize the effective utilization of visible light. After immobilizing laccase on mTiO2-CVs by adsorption method, the integrated catalyst (mTiO2-CVs2.5@lac) can be obtained. Compared with free laccase, mTiO2-CVs2.5, and commercial P25, mTiO2-CVs2.5@lac shows higher catalytic efficiency in the emerging contaminants degradation under visible light. Therefore, the photo-enzyme integrated catalyst presented in this study provides a promising platform for emerging organic pollutants degradation by combining the enzymes with photocatalysts