Assembling S-scheme heterojunction between basic bismuth nitrate and bismuth tungstate with promoting charges’ separation for accelerated photocatalytic sulfamethazine degradation

Abstract

The S-scheme heterojunction has garnered increasing attention due to its remarkable oxidation capacity and efficient separation of photogenerated carriers. In this study, a one-pot glycerol-assisted hydrothermal process was utilized to successfully synthesize S-scheme heterojunction photocatalysts comprising basic bismuth nitrate (BBN) and bismuth tungstate (BWO). Interestingly, the BBN/BWO heterogeneous photocatalysts exhibited the highest photocatalytic properties. The optimized product achieved the degradation of sulfamethazine (SMZ) within 1 h, with a kinetic constant (k) value of 0.05818 min−1. The degradation process was influenced significantly by ·O2− and h+ species. To determine the degradation pathway of SMZ in the presence of BBN/BWO-0.6, liquid chromatography–mass spectrometry (LC–MS) analysis was performed, which revealed a decrease in the toxicity of intermediates and products. The enhanced photocatalytic activity can be attributed to the internal electric field (IEF) of the S-scheme heterojunction between BBN and BWO, effectively promoting the separation of photogenerated carriers. This research presents a viable approach for developing S-scheme heterojunctions in SMZ photodegradation and other environmental applications.