Direct Z-scheme of WO3/GO decorated with silver nanoparticles for synergetic adsorption and photocatalytic activity for organic and inorganic water pollutants removal

Abstract

Synergism between adsorption and photocatalytic activity in heterocatalysis improve the overall performance of organic and inorganic pollutants removal. We report the WO3/GO composite immobilized on chitosan to enhance the adsorption process and decorated with Ag NPs for efficient photocatalytic visible light absorption. The ternary photocatalyst (x%Ag/WO3/GO (x = 0, 1, and 3) was characterized by SEM, TEM, XRD, FTIR, XPS, and UV–Vis techniques. The obtained results show that both GO sheets and CS enhanced the adsorption process, while Ag NPs enhance the photocatalytic performance of WO3/GO composite. As expected, the 3 %Ag/WO3/GO shows excellent catalytic and photocatalytic performance of the removal of organic (methylene blue, and p-nitrophenol) and inorganic (Cr6+) water pollutants. 3 %Ag/WO3/GO composite removes 98% of MB (20 min) in absence of light, where more than 98% of MB (8 min) and 95% of p-nitrophenol (8 min) were removed after visible light irradiation. Enhanced adsorption of MB and Cr6+ was attributed to π-π stacking and electrostatic attractive potential over the catalyst, respectively. Based on the experimental results and trapping experiments, the charge separation through the Z-scheme WO3/GO facilitate the charge migration and boost the photocatalyst performance.