Improved H 2 evolution under visible light in heterostructured SiC/CdS photocatalyst: Effect of lattice match

Abstract This paper reports the results of the photocatalytic activity of hydrogen production from water reduction using a composite catalyst of SiC/CdS with two types of heterointerfaces. Type 1 consists of hexagonal SiC and hexagonal CdS, while type 2 consists of hexagonal SiC and cubic CdS. It was found that type 1 composite exhibited an H 2 evolution rate four times greater than type 2, despite the similar bandgaps and electropotentials of both cubic and hexagonal CdS. Meanwhile, increased BET surface area, good distribution of CdS, strong light absorption and low carrier recombination were observed in type 1 heterointerface. Lattice match is thought to be achieved between two hexagonal compounds with a lattice-constant-relationship of 3 a H-CdS  = 4 a H-SiC . Further, the hexagonal SiC surface (006) was shown to have an affinity with the hexagonal CdS (002) facet due to their respective polar properties. The results of this paper demonstrate that lattice match plays an important role in forming efficient heterojunctions, which in turn enhance the photocatalytic performance of composite catalysts and will prove to be helpful in designing new composite photocatalytic systems.