Selective oxidation of aromatic alcohols to corresponding aromatic aldehydes using In2S3 microsphere catalyst under visible light irradiation

• In2S3 microsphere with ECB = −0.78 eV and EVB = 1.18 eV was prepared.
• In2S3 has an excellent performance for the conversion of aromatic alcohols.
• The conversion is 41.5% and the yield is 41.4% after being illuminated for 4 h.
• O2- and OH are the important oxidizing agents in the selective oxidation process.

Selective oxidation has become an alternative green way for organics synthesis and environmental remediation. In this paper, selective oxidation of aromatic alcohols to corresponding aromatic aldehydes under visible light irradiation using In2S3 microsphere as a photocatalyst was investigated. In2S3 microsphere with a band gap of 1.96 eV was prepared by using InCl3·4H2O and CH3CSNH2 as precursor. The structure and optical properties of In2S3 photocatalyst were investigated by X-ray powder diffraction, UV–vis diffuse reflectance spectroscopy, scanning electron microscopy, transmission electron microscopy, energy-dispersive spectroscopy, nitrogen adsorption–desorption and photoluminescence spectra. The results showed that the In2S3 microsphere has an excellent photocatalytic performance in the conversion of aromatic alcohols to corresponding aromatic aldehydes. For selective oxidation of benzyl alcohol, when illumination time is 4 h, the conversion reaches to 41.5%, and the yield is 41.4%. In2S3 microsphere as a photocatalyst has a good stability when it was used 5 times for selective oxidation of benzyl alcohol. O2- and OH are the important oxidizing agents in the photocatalytic process. The possible mechanism for the conversion of aromatic alcohols to corresponding aromatic aldehydes was proposed.

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