Hierarchically macro–mesoporous ZrO2–TiO2 composites with enhanced photocatalytic activity

Abstract

Hierarchically macro–mesoporous ZrO2–TiO2 composite materials were prepared based on a facile surfactant self-assembly method with titanium isopropoxide (TIP) and zirconium n-butoxide as precursors. The ZrO2 content in the composites (2.0–9.8%) was easily controlled by adjusting the molar ratio of the two precursors, while maintaining the porous structures of the materials. SEM results demonstrated that the ZrO2–TiO2 composites were featured by paralleled channels (50–500nm) and interparticle pores (~8nm) in the walls. The photocatalytic activities of the novel composites were remarkably higher than corresponding pure macro–mesoporous TiO2 and ZrO2 materials in the decomposition of Rhodamine B (RhB) under UV light radiation. The ZrO2–TiO2 sample with 6.9% of ZrO2 was proved to be the most efficient catalyst with degradation kinetic constant twice larger than that of the pure macroporous TiO2. Trapping experiments indicated that photogenerated holes and radicals were all vital to the photocatalytic process under UV light irradiation. ESR measurements gave the direct evidence that the active radicals •OH and O2•− were responsible for the photodecomposition of RhB.