Characterization and Optimization of Silver-Modified In(0.2)Cd(0.8)S-Based Photocatalysts

[Image: see text] In this research, we performed scanning electrochemical microscopy to screen M(x)(In(0.2)Cd(0.8))(1–x)S (M = V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Mo, Ru, Ag, W, Ir, Pt, and Te) photocatalyst arrays for efficient photoelectrochemical reaction. Doping 30% Ag to form the Ag(0.3)(In(0.2)Cd(0.8))(0.7)S electrode could result in the highest photocurrent, and also, the anode photocurrents were found to be 1 and 0.53 mA/cm(2) under UV–visible and visible light, respectively, comparatively higher than that of the In(0.2)Cd(0.8)S electrode (0.45 and 0.25 mA/cm(2)). The highest incident photo-to-current conversion efficiency of the Ag(0.3)(In(0.2)Cd(0.8))(0.7)S photocatalyst and In(0.2)Cd(0.8)S were found to be 64% (λ = 450 nm) and 57% (λ = 400 nm), respectively. The Mott–Schottky plots showed that In(0.2)Cd(0.8)S and Ag(0.3)(In(0.2)Cd(0.8))(0.7)S photoelectrodes could exhibit a flat-band potential of −0.85 and −0.55 V versus Ag/AgCl, respectively. Based on these findings, the superior photocatalytic activity of the Ag(0.3)(In(0.2)Cd(0.8))(0.7)S photoelectrode was mainly attributed to its high crystalline structure for efficient charge separation and reduction of charge recombination in the heterojunction of Ag(0.3)(In(0.2)Cd(0.8))(0.7)S and Ag(2)S.