Construction of R-TiO2/n-TiO2 heterophase photocatalysts for efficient degradation of organic pollutants

Abstract

In this study, a commercial rutile titanium dioxide (R-TiO2) with a particle size of 200–300 nm was used as a carrier to prepare R-TiO2/n-TiO2 photocatalysts through wet co-grinding in a stirred grinder, along with commercial TiO2 (n-TiO2). The structure of R-TiO2/n-TiO2, its photocatalytic degradation performance towards methyl orange, and the enhancement mechanism were investigated. The results demonstrated that under the optimized conditions of grinding time and n-TiO2 loading ratio, the prepared R-TiO2/n-TiO2 composite (with a n-TiO2 ratio of 30%) exhibited excellent photocatalytic degradation and recyclability. After 30 min of UV irradiation, the removal rate of methyl orange was 99%, which was comparable to that of pure n-TiO2 (degradation rate of 99.5%). The degradation rate of methyl orange using R-TiO2/n-TiO2 was 4.5 times higher than that of an equivalent proportion of n-TiO2, and the degradation performance remained nearly unchanged after five cycles of recycling. R-TiO2/n-TiO2 exhibits features such as effective dispersal and even distribution of n-TiO2 onto the surface of R-TiO2, coupled with the establishment of chemical bonding at the interface between the two constituents. The existence of R-TiO2 improved the dispersion of n-TiO2 and promoted the formation of an interfacial anatase/rutile heterophase junction, which are intrinsic mechanisms for enhancing the efficiency of TiO2 photocatalysis and achieving a reduction in the application process.