Characterization and Optimization of Silver-Modified In0.2Cd0.8S-Based Photocatalysts

ACS Omega. 2019 Dec 4;4(25):21214-21222. doi: 10.1021/acsomega.9b02685. eCollection 2019 Dec 17.

Abstract

In this research, we performed scanning electrochemical microscopy to screen M x (In0.2Cd0.8)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 Ag0.3(In0.2Cd0.8)0.7S electrode could result in the highest photocurrent, and also, the anode photocurrents were found to be 1 and 0.53 mA/cm2 under UV-visible and visible light, respectively, comparatively higher than that of the In0.2Cd0.8S electrode (0.45 and 0.25 mA/cm2). The highest incident photo-to-current conversion efficiency of the Ag0.3(In0.2Cd0.8)0.7S photocatalyst and In0.2Cd0.8S were found to be 64% (λ = 450 nm) and 57% (λ = 400 nm), respectively. The Mott-Schottky plots showed that In0.2Cd0.8S and Ag0.3(In0.2Cd0.8)0.7S 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 Ag0.3(In0.2Cd0.8)0.7S photoelectrode was mainly attributed to its high crystalline structure for efficient charge separation and reduction of charge recombination in the heterojunction of Ag0.3(In0.2Cd0.8)0.7S and Ag2S.