MoS2–CdS composite photocatalyst for enhanced degradation of norfloxacin antibiotic with improved apparent quantum yield and energy consumption

Abstract

This study introduces an advanced visible light-activated photocatalyst for the efficient degradation of norfloxacin in aqueous environments. CdS nanorods were synthesized on MoS2 through a solution-processable solvothermal method. The resulting MoS2–CdS composite exhibited exceptional photocatalytic oxidative degradation of norfloxacin antibiotic in aquatic media. The optimal degradation efficiency (87.5 %) and degradation rate constant (0.09 min−1) were achieved with the 10 wt% MoS2–CdS composite under light illumination, surpassing pure CdS nanorods by 1.5 and 2.25 times, respectively and the highest apparent quantum yield was obtained for 10 wt% MoS2–CdS composite, which is 1.5 times higher than CdS nanorod, while maintaining consistent experimental conditions. The electrical energy per order for the degradation of norfloxacin in an aqueous solution by 20 mg of CdS in 40 ml aqueous solution is 9.7 kW h m−3/order. This value reduces to 4.8 kW h m−3/order for an equal amount of 10 wt% MoS2–CdS composite. The transfer of photogenerated electrons from the CdS nanorod to MoS2 reduces the recombination probabilities of photogenerated charge carriers and consequently enhancing the photo degradation efficiency of the composite. This research may offer novel insights into the rational design and straightforward synthesis of bimetallic sulfide photocatalysts with commendable performance and cost-effectiveness for the degradation of antibiotics in aqueous environments.