Rational design of full-spectrum visible-light-responsive bimetallic sulfide BiS/CoS composites for high-efficiency photocatalytic degradation of naproxen and bacterial inactivation.

Photocatalytic water decontamination has emerged as a highly promising technology for efficient and rapid water treatment, harnessing sustainable solar energy as its driving force. In this study, we prepared visible-light active BiS/CoS composites for the degradation of naproxen (NPX) and the inactivation of Escherichia coli (E. coli). The homogeneous dispersion of CoS was stably integrated with BiS, resulting in a significant enhancement of the specific surface area, efficient utilization of visible light, and effective separation of photogenerated charge carriers. Consequently, this synergistic photocatalytic system greatly facilitated the successful degradation of NPX and the inactivation of E. coli under visible-light irradiation. Compared to the pure BiS and CoS catalysts, the BiS/CoS (1:2) composites displayed significantly enhanced photodegradation activity, achieving 96.46% (k = 0.2847 min) degradation of NPX within 90 min and maintaining good recyclability with no significant decline after six successive cycles. Additionally, the photocatalytic inactivation of E. coli results indicated that BiS/CoS composites exhibited excellent performance, leading to the inactivation of 7 log cfu mL of bacterial cells after 150 min of visible-light exposure. Scanning Electron Microscopy (SEM) and K ions leakage tests demonstrated that the destruction of the E. coli cell membrane structure resulted in cell death. The outcomes of this work suggest that BiS/CoS composites hold significant potential for treating water contaminated with antibiotic and microbial pollutants.