Photocatalytic mineralisation of herbicide 2,4,5-trichlorophenoxyacetic acid: enhanced performance by triple junction Cu–TiO2–Cu2O and the underlying reaction mechanism†
Abstract
A mild and facile photodeposition method was used to fabricate novel Cu–TiO2–Cu2O composite photocatalysts. Due to the in situ rectifying charge carrier separation and enhanced conductivity, the composites present superior photocatalytic activity, leading to more than 90% mineralisation of the toxic 2,4,5-trichlorophenoxyacetic acid herbicide. This result was confirmed by both TOC and UV-vis absorption measurements. The effect of active radicals on the photodegradation of the herbicide was further investigated in order to clarify the underlying mechanism, based on which a hole-dominated photooxidation mechanism was proposed. These results not only offer a green and economical method for constructing triple junction photocatalyst materials, but also shed new insight on the rational design of a low cost and high-efficiency photocatalyst for environmental remediation.