Photocatalytic hydrogen generation over CdS–metalosilicate composites under visible light irradiation

Abstract

In this work, we have synthesized CdS quantum dots and also supported CdS nanoparticles on ZSM-5 type metalosilicates (ferrisilicate and aluminosilicate) as CdS–metalosilicate composites. The photocatalytic activity for hydrogen production over the prepared catalysts was investigated. It can be observed that the synthesis of CdS quantum dots by a solvothermal method results in the enhancement of photocatalytic activity of this semiconductor in comparison to other procedures, which has been reported previously. Our objective was to improve the photocatalytic activity of our synthesized CdS nanoparticles; for this purpose, we have supported CdS on metalosilicates and investigated their photocatalytic activity. These composites show high efficiency for hydrogen production under visible light irradiation. This suggests that, due to the high surface area of metalosilicates, the effective and homogenous dispersion of CdS particles on the external surface or within the pores of metalosilicate can be achieved by supporting the nanoparticles which inhibits the agglomeration of the formed semiconductor. We have thus distinguished that supporting of CdS nanoparticles leads to improvement of the photocatalytic activity in water reduction; so that the hydrogen production rate for CdS–metalosilicate composite was about 11 mmol h⁻¹ g_cat⁻¹; which is significantly higher than that of unsupported CdS nanoparticles.