Effect of Indium doping on the photoelectrochemical and photocatalytic properties of zinc sulphide

Abstract

In this article, the visible light enhanced photoelectrochemical and photocatalytic properties for nano-sized Indium doped Zinc Sulphide compared to undoped ZnS had been reported. Both ZnS and In doped ZnS (In-ZnS) were synthesized through soft chemical route by a co-precipitation method. ZnS and In doped ZnS existed as single phase having cubic structure. These samples were nano-sized with a particle size of approximately 24nm. SEM images revealed the presence of aggregated particles with a wide distribution in the particle size. UV–visible Diffused Reflectance Spectra showed improved visible light absorption for the doped sample as compared to the undoped sample. X-ray photoelectron studies indicated the presence of indium as In3+ in In-ZnS. Photoluminescence studies suggested the presence of both zinc and sulfur vacancies in these samples. After the doping of ZnS with In, there was an increase in photocurrent under visible light irradiation. The doped sample also exhibited enhanced photocatalytic activity for hydrogen generation. A good correlation between photocatalytic and photoelectrochemical properties was seen for both ZnS and In doped ZnS. The improvement in In doped ZnS has been attributed to the increased visible light absorption arising due to the decreased band gap of the doped sample.