A simple and environmentally friendly method of preparing sulfide photocatalyst

This paper reports the preparation of (Agln) x Zn 2(1-x) S 2 solid solutions from acidic aqueous solutions consisting of silver nitrate, indium nitrate, zinc nitrate, and thioacetamide, without using toxic H 2 S gas. The reaction sequence of this multicomponent material was investigated, as well as the post thermal treatment conditions. The formation of quaternary semiconductor solid solutions after 800°C annealing were determined by X-ray diffraction. The peaks in the XRD patterns shifted to higher angles with an increase of [Zn]/[In] in the precursor solutions. Band gaps of the (Agln) x Zn 2(1-x) S 2 solid solutions were estimated to be 2.11-2.45 eV by diffuse reflection UV-Vis spectra. In addition, the band gap energy increased with [Zn]/[In] accordingly. The precipitates after heat treatment had a layered structure, as revealed by SEM; the compositions were analyzed by EDS. The photocatalytic H 2 evolution rates in sacrificial reagents under a 300W Xe lamp of Pt-loaded (Agln) x Zn 2(1-x) S 2 solid solutions were measured. A H 2 evolution of 340 μmol/h for 0.5 g photocatalyst was obtained. The particles retained the photocatalytic activity for at least 100h. This study demonstrates that AglnS 2 -ZnS solid solution particles can be prepared from a completely aqueous route.

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