Facile fabrication of mpg-C3N4/Ag/ZnO nanowires/Zn photocatalyst plates for photodegradation of dye pollutant

In the present study, mpg-C3N4/Ag/ZnO NWs/Zn photocatalyst plates were fabricated through facile dip-coating process of silver (Ag) and mesoporous graphitic carbon nitride (mpg-C3N4) onto zinc oxide nanowires (ZnO NWs) previously formed by electrochemical anodizing of Zn plates. The structure, optical and electrochemical characterizations of the fabricated samples were investigated by XRD, FESEM, EDX, TEM, FTIR, BET, PL, UV–vis DRS, and EIS analyses. To evaluate the photocatalytic activity of the plates, the main key factors such as number of photocatalyst plates, dye concentration, initial pH, and reaction time for the degradation of Direct Orange 26 (DO26) dye under ultraviolet (UV) light illumination were studied. The best photocatalytic efficiency of 94 % was achieved using four photocatalyst plates, 10 mg/L DO26, and pH = 6 in 120 min of reaction time. The integration of the mpg-C3N4/Ag/ZnO NWs/Zn plates, adsorption, and photolysis inferred the existence of a synergy index of 5 for the degradation of target pollutant. In the presence of edetate disodium (EDTA-2Na) and ethanol (EtOH), degradation efficiency of DO26 was remarkably dropped to 43.6 % and 19.3 % by the photocatalytic process respectively, indicating the major role of h+ and OH in the destruction of target molecules. The overwhelming photocatalytic mechanism of the photocatalyst was further clarified for the elimination of DO26. The fabricated photocatalyst demonstrated remarkable stability and recyclability for four consecutive catalytic cycles. Fabrication of the mpg-C3N4/Ag/ZnO NWs/Zn plates is anticipated to be a rational design for photocatalytic degradation of various pollutants.