Tuning the charge transfer route by p-n junction catalysts embedded with CdS nanorods for simultaneous efficient hydrogen and oxygen evolution

Overall solar water splitting into H-2 and O-2 using visible light responsive photocatalyst has been considered as a clean, green, and renewable system. CdS with a suitable bandgap (2.25 eV) and band position was for a long time not considered as a promising candidate for overall solar water splitting because of its serious photo-corrosion and rapid charge recombination, although it has considerable photocatalytic activity for H-2 generation in a sacrificial agent containing electrolyte. Here, we design a new sandwich-like architecture using CdS nanorods embedded in a p-n junction of MoS2/N-RGO which serves as a novel photocatalytic system that could promote overall water splitting in natural water. It was found that the p-n junction of MoS2/N-RGO not only works as the HER and OER electrocatalyst for H-2 and O-2 generation respectively, but also facilitates charge separation by its inner electric field. Compared to well-defined thermodynamically favored charge transport, the new charge transfer route in MoS2/CdS/N-RGO splits natural water, resulting in an essential change of the carrier separation mechanism and high anti-corrosion.