Zn_(2x)(GuIn)_(1-x)S_2 photocatalysts synthesis by a hydrothermal process using H_4EDTA as complexing agent

摘要

The study of the Zn_(2x)(CuIn)_(1-x)S_2 (0≤x≤1) solid solutions formation by hydrothermal synthesis using ethylenediaminetetraacetic acid (H_4EDTA) as a complexant and surfactant agent is reported for the first time. Different synthesis parameters were varied: the H_4EDTA concentration, the initial pH value, the Tu concentration, the duration and temperature of autoclaving process. The as obtained powders were characterized by X-ray powder diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM) and UV/vis/NIR diffuse reflection spectroscopy (DRS). The XRD and EDX results show that, with a careful adjustment of the reaction conditions, especially of the H_4EDTA concentration and initial pH value of the precursor solution, a mixture of solid solutions with sphalerite type structure can be obtained, which transforms into a single phase solid solution after heat treatment. The particles, as revealed by SEM investigations, have nanoporous hexagonal microplates morphology, about 1 μm thick and several microns in diameter. The Gu_(0.159)In_(0.111)Zn_(1.778)S_2 photo-catalyst obtained by this method presents photocatalytic activity for hydrogen evolution from aqueous solutions containing S_(2-) ions as sacrificial agent, even without cocatalyst.