This communication presents our recent results that the activity of photocatalytic H2 production can be significantly enhanced when a small amount of MoS2 is loaded on CdS as cocatalyst. The MoS2/CdS catalysts show high rate of H2 evolution from photocatalytic re-forming of lactic acid under visible light irradiation. The rate of H2 evolution on CdS is increased by up to 36 times when loaded with only 0.2 wt % of MoS2, and the activity of MoS2/CdS is even higher than those of the CdS photocatalysts loaded with different noble metals, such as Pt, Ru, Rh, Pd, and Au. The junction formed between MoS2 and CdS and the excellent H2 activation property of MoS2 are supposed to be responsible for the enhanced photocatalytic activity of MoS2/CdS.

Photocatalytic H 2 production on MoS 2 /CdS photocatalysts in the presence of different sacrificial reagents under visible light (λ > 420 nm) has been investigated. The transformation process of the Mo species loaded on CdS, together with the junctions formed between MoS 2 and CdS, was clearly demonstrated with X-ray photoelectron spectroscopy and transmission electron microscopy. Photocatalytic H 2 evolution was optimized for MoS 2 /CdS catalysts. The 0.2 wt % MoS 2 /CdS catalyst calcined at 573 K achieves the highest overall activity for H 2 evolution, and the 0.2 wt % MoS 2 /CdS catalyst demonstrates even higher activity than the 0.2 wt % Pt/CdS, irrespective of different sacrificial reagents used. The junctions formed between MoS 2 and CdS play an important role in enhancing the photocatalytic activity of MoS 2 /CdS catalysts. Electrochemical measurements indicate that MoS 2 is an excellent H 2 evolution catalyst, which is another very important factor responsible for the enhancement of the photocatalytic activity of MoS 2 /CdS catalysts.

A molecular device with a photocathode for hydrogen generation has been successfully demonstrated, based on an earth abundant and inexpensive p-type semiconductor NiO, an organic dye P1 and a cobalt catalyst Co1.