Wide spectrum responsive CdS/NiTiO3/CoS with superior photocatalytic performance for hydrogen evolution

Abstract

A wide spectrum responsive CdS/NiTiO₃/CoS nanocomposite was successfully prepared via a facile one pot reaction and was fully characterized. The as-obtained CdS/NiTiO₃/CoS nanocomposite shows absorption in both visible and NIR regions due to the introduction of NiTiO₃. The hydrogen (H₂) evolved over the CdS/NiTiO₃/CoS nanocomposite under whole visible to NIR irradiation in 5 h was 2381 μmol, which is 22-fold that produced over pure CdS. The superior photocatalytic performance over the CdS/NiTiO₃/CoS nanocomposite can be ascribed to its wide spectrum response and the formation of a CdS/NiTiO₃ heterojunction as well as the deposition of CoS as a cocatalyst for H₂ evolution. The formation of the heterojunction of CdS/NiTiO₃ to suppress the recombination of photo-generated charge carriers over the CdS/NiTiO₃/CoS nanocomposite was well demonstrated by PL studies. Moreover, the photo-corrosion of CdS in the CdS/NiTiO₃/CoS nanocomposite induced by the hole-oxidation of lattice S²⁻ can be inhibited due to the morphology change of CdS from nanoparticles in pure CdS to nanoflakes in the CdS/NiTiO₃/CoS nanocomposite. This study can provide some guidance for the development of wide spectrum responsive photocatalysts for H₂ evolution.