Simultaneous degradation of SMX for efficient nitrogen fixation to ammonia and hydrogen evolution using AgVO3@rGO-Ag3PO4 (110) heterojunction

Abstract

The simultaneous degradation of organic pollutants and generation of value-added compounds like ammonia and hydrogen energy has recently gained considerable attention in photocatalysis. The present study deals with successful preparation of novel AgVO3 nanowire@rGO-tetrahedral Ag3PO4 (110) (AGA) heterojunction and utilized for enhanced generation of NH3 and H2 from N-containing antibiotic sulfamethoxazole (SMX) under visible light. The prepared catalyst was well characterized by XRD, SEM, TEM and XPS to confirm the formation of heterojunction. The results indicated that the composite exhibited 546.0 μmol g−1 of hydrogen evolution rate, which is approximately 3.6 (153.6 μmol g−1) and 5.1 (108.7 μmol g−1) times higher than the pure AgVO3 and Ag3PO4 respectively after 6 h. Similarly, 38.3 mg L−1g−1 of NH3 generation was observed during 6 h of SMX degradation, which is about 1.9 and 2.8 times higher than the pure AgVO3 (20.1 mg L−1g−1) and Ag3PO4 (13.7 mg L−1g−1) respectively. The formation of heterojunction between AgVO3 and Ag3PO4 not only promotes the transfer of electron but also prevents the recombination which eventually enhances the catalytic conversion of N-element to NH3 and for H2 generation during water splitting. Furthermore, the plausible degradation pathway in SMX was proposed and the results revealed that the SMX was mineralized by the composite further converted to NH3 and generates H2 during the degradation process. Thus, our study provides new insights into novel photocatalytic treatment methodologies for simultaneous degradation of SMX to produce NH3 and H2 as value-added compounds from antibiotic wastewaters during water treatment process.