High efficient photocatalytic selective oxidation of benzyl alcohol to benzaldehyde by solvothermal-synthesized ZnIn2S4 microspheres under visible light irradiation

• Marigold-like ZnIn2S4 microspheres were synthesized by a solvothermal method.
• The solvents have a remarkably influence on the morphology and properties of samples.
• It is the first time to apply ZnIn2S4 for selective oxidation of benzyl alcohol.
• ZnIn2S4 shows high photocatalytic activity for selective oxidation of benzyl alcohol.

Hexagonal ZnIn2S4 samples have been synthesized by a solvothermal method. Their properties have been determined by X-ray diffraction, ultraviolet–visible-light diffuse reflectance spectra, field emission scanning electron microscopy, nitrogen adsorption–desorption and X-ray photoelectron spectra. These results demonstrate that ethanol solvent has significant influence on the morphology, optical and electronic nature for such marigold-like ZnIn2S4 microspheres. The visible light photocatalytic activities of the ZnIn2S4 have been evaluated by selective oxidation of benzyl alcohol to benzaldehyde using molecular oxygen as oxidant. The results show that 100% conversion along with >99% selectivity are reached over ZnIn2S4 prepared in ethanol solvent under visible light irradiation (λ>420 nm) of 2 h, but only 58% conversion and 57% yield are reached over ZnIn2S4 prepared in aqueous solvent. A possible mechanism of the high photocatalytic activity for selective oxidation of benzyl alcohol over ZnIn2S4 is proposed and discussed.

Marigold-like ZnIn2S4 microspheres were synthesized by a solvothermal method. The high visible photocatalytic activities of ZnIn2S4 were evaluated by selective oxidation of benzyl alcohol to benzaldehyde under mild conditions. Figure optionsDownload as PowerPoint slide