Construction of TiO2(B)/Anatase Heterophase Junctions via a Water-Induced Phase Transformation Strategy for Enhanced Photocatalytic Hydrogen Production.

Abstract

The development of facile and green solution-phase routes toward the fabrication of TiO2-based heterophase junctions with a delicate control of phase and structure is a challenging task. Herein, we report a simple and convenient method to controllably fabricate TiO2(B)/anatase heterophase junctions, which was successfully realized by utilizing the ideal great solvent of water to treat the presynthesized TiO2(B) nanosheet precursor at a low temperature of 80 °C. On the basis of phase structure transformation and morphology evolution data, the formation of these TiO2(B)/anatase heterophase junctions was reasonably explained by a novel water-induced TiO2(B) → anatase phase transformation mechanism. Benefiting from the desirable structural and photoelectronic advantages of more exposed active sites, enhanced light absorbance, and promoted separation of photogenerated electron-hole pairs, the thus-transformed TiO2(B)/anatase heterophase junctions exhibit fascinating photocatalytic performance in water splitting. Specifically, with the help of Pt as a cocatalyst and methanol as a sacrificial agent, the H2 production rate of optimized TiO2(B)/anatase heterophase junction reaches 6.92 mmol·g-1·h-1, which is almost 7.1 and 2.1 times higher than those of the pristine TiO2(B) nanosheets and the final anatase nanocrystals. More interestingly, the TiO2(B)/anatase heterophase junction also delivers prominent activity toward pure water splitting to simultaneously produce H2 and H2O2, with evolution rates of up to 1.10 and 0.55 mmol·g-1·h-1, respectively. Our work may advance the facile green solvent-mediated synthesis of metal oxide-based heterophase junctions for applications in energy- and environmental-related areas.