Flexible roles of TiO2 in enhancing carrier separation for the high photocatalytic performance of water treatment under different spectrum sunlight

Abstract

Construction of heterogeneous-photocatalysts is an effective mean for enhancing charge separation, however, the specific roles of the individual components have not been thoroughly explored. In this article, a heterogeneous-photocatalyst, TiO2/MoO3-x, was constructed, revealing that the two components, TiO2 and MoO3-x, play varying roles under different light spectra. Under full spectrum light, an S-scheme mechanism was achieved, which preserved the high oxidizing and reducing property of MoO3-x and TiO2, facilitating an augmented generation of reactive oxygen species (ROS). Under visible light, the MoO3-x functioned as the donor of hot electrons and the TiO2 served as the receptor platform for these electrons. The presence of the interfacial electric field enabled the transfer of hot electrons, leading to an enhanced ROS generation. Consequently, the TiO2/MoO3-x achieved high photocatalytic activity under both full spectrum and visible light. The optimized TiO2/MoO3-x catalyst demonstrated outstanding antibacterial efficacy, achieving eradication rates of 98.1 % for Staphylococcus aureus, and 99.6 % for Escherichia coli respectively. Additionally, it exhibited substantial degradation activity with a rate of 0.028 min−1 for Rhodamine B (50 mg/L). Furthermore, the TiO2/MoO3-x membrane removed approximately 81.2 % of bacteria from surface water, underscoring the potential of the designed membrane in water purification systems. This article explored the distinct roles and corresponding charge transfer mechanisms of the TiO2 and MoO3-x under full spectrum or visible light, offering innovative ideas for the design of full-spectrum photocatalysts with high efficiency. The straightforward design of membrane-based filtering device demonstrated wide applications for treating wastewater for the removal of dye and bacterial contamination.