A hybrid of CdS/HCaNbO ultrathin nanosheets for promoting photocatalytic hydrogen evolution.

A hybrid of CdS/HCaNbO ultrathin nanosheets was synthesized successfully through a multistep approach. The structures, constitutions, morphologies and specific surface areas of the obtained CdS/HCaNbO were characterized well by XRD, XPS, TEM/HRTEM and BET, respectively. The TEM and BET results demonstrated that the unique structural features of CdS/HCaNbO restrained the aggregation of CdS nanoparticles as well as the restacking of nanosheets effectively. HRTEM showed that CdS nanocrystals of about 25-30 nm were firmly anchored on HCaNbO nanosheets and a tough heterointerface between CdS and the nanosheets was formed. Efficient interfacial charge transfer from CdS to HCaNbO nanosheets was also confirmed by EPR and photocurrent responses. The photocatalytic activity tests (λ > 400 nm) showed that the optimal hydrogen evolution activity of CdS/HCaNbO was about 4 times that of the bare CdS, because of the efficient separation of photo-generated carriers.