Charge transfer mechanism in Z-scheme ternary heterojunction photocatalysts of AgCl/CoWO4/Ag and its role in enhancing photocatalytic performance

With the rapid advancement of modern industry and population growth, unrestrained discharge of industrial effluent and domestic sewage has caused severe environmental pollution, which poses a severe challenge to human habitat. Owing to the unique eco-friendly characteristics, photocatalytic technology has emerged as a highly promising approach in the wastewater treatment very recently. Z-scheme heterojunction ternary photocatalysts of “ x · AgCl/ y · CoWO₄/Ag” were ingeniously designed and developed in this study, exhibiting exceptionally high photocatalytic activity for degrading micropollutants in wastewater compared with single-component photocatalysts. For instance, photocatalytic activity of AgCl/CoWO₄/Ag (reflected by the reaction kinetic parameter k ) is 7.7 times that of AgCl and 313 times that of CoWO₄, respectively. The experimental results and analysis revealed a typical Z-scheme charge transfer mechanism in these ternary photocatalyst heterojunctions, thereby confirming the structural characteristics of Z-scheme heterojunction. Furthermore, the ternary photocatalysts retained the reaction activity with virtually no change after undergoing five cycles of catalytic experiments, highlighting its excellent stability. Consequently, an underlying mechanism was proposed herein to account for the enhanced photocatalytic properties. It is believed that such ternary Z-scheme heterojunction materials expand halide-based heterojunction construction methods and promise significant implications for environmental remediation.