Reduced Graphene Oxide–SnSe Nanocomposite Photocatalyst with High Apparent Quantum Yield for the Photodegradation of Norfloxacin

Abstract

A visible-light-responsive photocatalyst, comprising reduced graphene oxide (RGO) modified tin selenide (SnSe), was fabricated via a cost-effective, one-pot, easy-to-achieve, single-step solvothermal method. The Brunauer−Emmett−Teller analysis shows SnSe with a specific surface area of about 0.3 m 2 g −1 , while RGO−SnSe significantly increases it to 8.44 m 2 g −1 . The photocatalytic kinetics of the RGO−SnSe composite revealed a pseudo-first-order reaction mechanism during the degradation of norfloxacin antibiotics in an aqueous environment. Results indicated that an increase in RGO content in the composites led to enhanced degradation efficiency and apparent quantum yield, reaching maximum values of 90.7 and 11.37%, respectively, at a specific RGO loading of 37 wt %. These values were found to be 3.6 times higher than pure SnSe. However, further augmentation of RGO resulted in a decline in both efficiency and yield. The enhanced catalytic performance can be attributed to the improved synergy between RGO and SnSe. The electrical energy per order was calculated to assess the energy efficiency of the photocatalytic degradation process, yielding a low value of 6.7 kW h m −3 /order for the RGO−SnSe composite with a loading of 0.75 mg/L RGO−SnSe catalyst. The photocatalytic activity of the composite remained nearly unchanged for at least four repeated cycles without any degradation of the catalyst. This outcome underscores the efficacy of the RGO−SnSe composite as an efficient and sustainable technique for antibiotic degradation with a high apparent quantum yield and low energy consumption.