Influence of Zn concentration in the activity of Cd 1− xZn xS solid solutions for water splitting under visible light

Abstract

Solid solutions Cd 1− x Zn x S with different Zn concentration (0.2 < x < 0.35) are investigated in the production of hydrogen from aqueous solutions containing SO 3 2−/S 2− as sacrificial reagents under visible light. Textural, structural and surface catalyst properties are determined by N 2 adsorption isotherms, UV–vis spectroscopy, SEM and XRD and related to the activity results in hydrogen production from water splitting under visible light irradiation. It is found that the crystallinity and energy band structure of the Cd 1− x Zn x S solid solutions depend on their Zn atomic concentration. The hydrogen production rate is found to increase gradually when the Zn concentration on photocatalysts increases from 0.2 to 0.3. Subsequent increase in the Zn fraction up to 0.35 leads to lower hydrogen production. Variation in photoactivity is analyzed in terms of changes in crystallinity, level of conduction band and light absorption ability of Cd 1− x Zn x S solid solutions derived from their Zn atomic concentration.