In Situ Formation of Leaf-Like Ag2S/CdS Heterojunction Photocatalyst Harnessing Vis–NIR Light for Photodegradation of Organic Pollutants

Abstract The Ag 2 S/CdS composite photocatalyst with a leaf-like structure was synthesized by loading the Ag 2 S nanoparticles on the surface of the hydrothermally synthesized CdS particles. The UV–Vis–NIR absorption spectroscopy results reveal that the Ag 2 S/CdS composite photocatalyst exhibits a wide-spectrum response from ultraviolet (UV) to near-infrared (NIR), demonstrating its potential for effective utilization of solar energy. The scanning and transmission electron microscopic observations show that Ag 2 S nanoparticles with the size of about 20 nm are successfully embedded on the surface of leaf-like structure of CdS. Among the samples loaded with different molar percentages of Ag 2 S nanoparticles, the 5%-Ag 2 S/CdS composite photocatalyst exhibits a higher photocatalytic efficiency than the individually synthesized CdS and Ag 2 S for the degradation of Rhodamine B (RhB) and methyl orange (MO) under LED visible light irradiation. Furthermore, the 5%-Ag 2 S/CdS composite photocatalyst also exhibits a photocatalytic activity for the degradation of RhB under 850 and 940 nm monochromatic light irradiation. The results of the photocatalytic activity tests performed with various scavengers confirm that ·O 2 − plays a key role in the photodegradation of RhB. An enhanced photocatalytic performance of the Ag 2 S/CdS composite photocatalyst is directly attributed to the formation of a heterojunction between Ag 2 S and CdS. The developed composite photocatalyst can harness a greater share of the solar spectrum from visible to near infrared region and generate the photoinduced charge carriers more efficiently. Graphical Abstract