Enhanced photogenerated carrier separation in CdS quantum dot sensitized ZnFe2O4/ZnIn2S4 nanosheet stereoscopic films for exceptional visible light photocatalytic H2 evolution performance

Abstract

CdS quantum dot sensitized ZnFe₂O₄/ZnIn₂S₄ nanosheet stereoscopic films were synthesized through two sequential solvothermal processes and the ionic layer adsorption-reaction method. The hydrophilic ZnIn₂S₄ nanosheet stereoscopic film was pre-prepared to act as a suitable host material, and then ZnFe₂O₄ nanoparticles and CdS quantum dots were uniformly decorated on the surface of the ZnIn₂S₄ nanosheet stereoscopic film to form a ternary heterostructure stereoscopic film. The band structure difference in the ternary heterostructure can promote the spatial separation and transport efficiency of photogenerated charge carriers. Meanwhile, the composite stereoscopic film has significant structural advantages and can provide a large amount of reaction active sites and outstanding visible light utilization. The superhydrophilic surface contributes to interface contact of catalyst/solution and gas detachment. These positive factors led to a significantly enhanced photocatalytic H₂ evolution activity of the CdS/ZnFe₂O₄/ZnIn₂S₄ ternary heterostructure film in comparison with the pristine ZnIn₂S₄ and binary heterostructure film photocatalysts. The optimized CdS/ZnFe₂O₄/ZnIn₂S₄ ternary heterostructure film demonstrates the highest H₂ production rate of 79.0 μmol h⁻¹, which surpasses that of ZnIn₂S₄ by more than 3.2 times. This synthesis strategy can be applicable for the facile synthesis of other visible-light-driven composite film catalysts.