Electron bridge rGO synergized with Z-scheme ZnTe/WO3 heterojunction for simultaneous and efficient tetracycline degradation and Cu (II) reduction

Abstract

Z-scheme heterojunction photocatalysts can restrain carriers’ recombination while retaining high redox capacity. Herein, a novel ZnTe/rGO/WO3 (ZRW) Z-scheme heterojunction was constructed for simultaneous removal of TC and Cu (II) from wastewater. The highly conductive rGO served as a bridge connecting the ZnTe and WO3 whereby forming a tight interaction interface, beneficial to carriers transfer and separation. The removals of TC and Cu (II) using the optimized ZRW-10% achieved 90.6% and 89.5% within 150 min of light exposure, which were much higher than those from the ZnTe and WO3. Results of free radical trapping experiments and electron spin resonance analysis suggested that·O2- and·OH were the key active species for TC oxidation while e- dominated Cu (II) reduction. Based on the identified TC degradation intermediates, two possible degradation pathways for TC were proposed, and the ecotoxicity of most intermediates were less than TC. This study can advance research development of designing efficient Z-scheme photocatalyst and elimination of complex pollutants.