Solar light-driven photocatalytic degradation potential of g-C3N4 based binary chalcogenides (AgBiS2/g-C3N4)

Abstract

Fabrication of the AgBiS2 loaded on g-C3N4 was achieved via a hydrothermal route. The novel composite photocatalyst was successfully characterized using Scanning electron microscopy (SEM), Fourier transform infrared (FTIR), Energy dispersive X-ray (EDX), X-ray diffraction (XRD) techniques, and XPS analysis. The synthesized composite (AgBiS2/g-C3N4) was employed for the photocatalytic degradation of methylene blue (MB) under sunlight. The composition of cheaper and visible light active photocatalyst i.e. g-C3N4, with AgBiS2 was advantageous in terms of effective charge separation -due to heterojunction-, and surface morphology. Besides, the energy band gap reduction (owing to the addition of g-C3N4 in AgBiS2) facilitates sunlight-driven photocatalysis. The influencing parameters such as pH, oxidant dose, AgBiS2/g-C3N4 dose, dye concentration, and irradiation time were analyzed for the selection of the well-suited reaction conditions. The interaction of pollutant molecules with the catalyst surface was investigated based on the pHpzc results. Under preferred conditions (such as dye = 10 ppm, pH = 8, catalyst = 40 mg/100 mL, H2O2 = 12 mM, and time = 180 min) the AgBiS2/g-C3N4 exhibited ∼93% photocatalytic degradation of MB. The key radicals were determined using a radical trapping experiment. The reaction kinetic of the proposed study was also studied using 1st and 2nd order kinetic models. The combined influences of effecting parameters were checked by Response surface methodology.