Z-scheme TiO2−x@ZnIn2S4 architectures with oxygen vacancies-mediated electron transfer for enhanced catalytic activity towards degradation of persistent antibiotics

Abstract

In photocatalysis as a “green chemistry” technology, the development of efficient strategies to fabricate high-performance micro-nano photocatalysts with robust solar light utilization to deal with persistent pharmaceutical products in the wastewater system is crucially important. In order to improve the photoelectric activity, interfacial charge transfer, and reduce the recombination rate of photo-generated electron-hole pair, a Z-scheme TiO2−x @ZnIn2S4 heterojunction was prepared by hydrothermal method. The morphological structure and optical properties of the prepared catalysts were extensively characterized. Experimental results show that the rich of oxygen vacancies in TiO2−x benefits the formation of local defect energy levels at the bottom of the CB, which can be advantageous to broaden the light absorption range. Likewise, the TiO2−x @ZnIn2S4 showed 12.4-fold and 7.70-fold higher photocatalytic performance pristine TiO2−x and ZnIn2S4 towards the degradation of tetracycline hydrochloride (TCH) and nitrofurantoin (NFT) in real water matrix and solution water. Furthermore, the photo-decomposition pathway of NFT was proposed by HPLC-MS, and the Z-scheme electron transfer mechanism in TiO2−x @ZnIn2S4 heterojunction was proposed and discussed in detail. This work emphasizes a facile method for designing high-efficiency oxygen vacancy mediated titanium-based photocatalysts with excellent photoactivity in environmental remediation.