Reduced graphene oxide-assisted graphitic carbon nitride@ZnO rods for enhanced physical and photocatalytic degradation

Abstract

Herein, ternary nano photocatalysts of reduced graphene oxide assisted graphitic carbon nitride and zinc oxide were investigated to degrade the hazardous methylene blue (MB) dye in aqueous solution. The ternary nanocatalyst, rGO@g-C3N4/ZnO, showed increased photocatalytic MB degradation of 91.5% under visible light after 70 min compared with ZnO (55.31%), g-C3N4 (16.83%), and g-C3N4/ZnO (73.83%). MB degradation could be altered by changing the experimental conditions. The catalyst dosage and irradiation time were varied, and changes in the rGO@g-C3N4/ZnO degradation efficiency were observed. In addition to the experimental observations, a theoretical prediction of MB degradation was proposed through response surface methodology, and a preliminary equation was identified. A photocatalytic degradation mechanism that explained the role of rGO and g-C3N4 to enhance the photocatalytic efficiency of rGO@ g-C3N4/ZnO was also proposed based on the experimental results and theoretical modeling. The optical, structural, and chemical state and the surface morphology were also investigated, and the findings support the suggested photocatalytic mechanism. The findings of this study could be useful for applying nanocatalysts to degrade organic dyes.