Fabrication of Ag-decorated La0.9Ag0.1FeO3 for efficient photocatalytic degradation of tetracycline under visible light with the assistance of water oxidation

Abstract

The photocatalytic conversion of molecular O2 into reactive oxygen species, such as superoxide radicals (·O-2), has become the focus in the oxidative removal of organic pollutants. Nevertheless, the inefficient light absorption, limited adsorption of O2, and the fast recombination rate of photo-induced electron-hole pairs considerably impede the conversion efficiency of the photocatalysts. Herein, we report the synthesis of Ag@LAFO photocatalyst, which contains Ag nanoparticles (NPs)-decorated LAFO (Ag-substituted LaFeO3), to enhance the photodegradation efficiency of tetracycline (TC) with the assistance of water oxidation. Structural and spectroscopic analyses confirmed the successful decoration of Ag NPs on LAFO, which was prepared by substituting 10% La with Ag. The efficiency of TC photocatalytic degradation rate of Ag@LAFO is 76.25%, which is 6.1-fold higher than that of pure LFO (12.41%). The trapping experiment of active radicals verified that ·O-2 was crucial in the decomposition of TC molecules and was continuously supplied by the reduction of O2 molecules supported by photocatalytic water oxidation. Moreover, the Ag NPs in Ag@LAFO were found to be crucial for boosting the capture of photo-induced electrons and the activation of adsorbed O2. This study offers a new perspective on the conversion of O2 to ·O-2 with the assistance of photocatalytic water oxidation for photocatalytic degradation of organic pollutants.