Fabrication of Ag decorated g-C3N4/LaFeO3 Z-scheme heterojunction as highly efficient visible-light photocatalyst for degradation of methylene blue and tetracycline hydrochloride

摘要

The discharge of industrial wastewater poses serious concerns to the environment and human health. Therefore, urgent development of simple and efficient catalysts for removal of pollutants is required. In this study, a novel ternary nanocomposite Ag/g-C3N4/LaFeO3 (A/CN/LFO) was synthesized for the degradation of dye and pharmaceutical wastewater. The catalyst was prepared by decorating Ag nanoparticles (NPs) on g-C3N4/LaFeO3 (CN/LFO) Z-scheme heterojunction and formation of Schottky junctions with LaFeO3 (LFO) and g-C3N4 (CN). The formed hybrid structure between metal and Z-scheme heterojunction induced directional transfer of electrons or holes from the Z-scheme heterojunction to metal, providing maximum separation between electrons and holes for more efficient redox reactions. Consequently, the ternary nanocomposite displayed optimized efficiencies toward the photocatalytic degradation of methylene blue (MB) and tetracycline hydrochloride (TC) under visible-light irradiation, estimated to 98.97% (90 min) and 94.93% (120 min), respectively. These values were almost 4.81 times and 3.88 times higher than those of pristine LaFeO3, respectively. The charge transfer mechanism and pollutant degradation pathway were also studied. The data revealed that Ag decorated Z-scheme heterojunction showed efficient light absorption and separation of photogenerated carriers, which might be useful for large-scale practical applications related to wastewater treatment and pollution control.