Optimizing electron structure of Zn-doped AgFeO2 with abundant oxygen vacancies to boost photocatalytic activity for Cr(VI) reduction and organic pollutants decomposition: DFT insights and experimental

Abstract

The density functional theory (DFT) not only is indispensable to calculate the electronic structure and chemical property of photocatalysts, but also provides guidance to the understanding of the mechanisms involved in photocatalysis. Herein, a novel Zn doped AgFeO2 was successfully constructed for enhancement of Cr(VI) reduction and azophloxine decomposition under visible light irradiation. The DFT calculation was employed to set up a Zn doped AgFeO2 model to simulate its split Zn 3d levels shift to lower energy to optimize the band structure. With Zn doped, the AgFeO2 exhibit enhanced reducing capacity. As expected, compared to unmodified AgFeO2, Zn doped AgFeO2 can reduce and remove more than 90% of Cr(VI). Based on theoretical analysis and systematic experiments, the enhanced photocatalytic of Zn doped AgFeO2 were arisen from superoxide radical (O2−) generation and photocarrier transfer via oxygen vacancies (OVs) enrichment, and the OVs would provide coordinatively unsaturated sites for Cr(VI) adsorption. We expect this work can provide new insights into the photocatalytic utilization of AgFeO2.