Fabrication of hydrophilic S/In₂O₃ core–shell nanocomposite for enhancement of photocatalytic performance under visible light irradiation

Graphical abstract: - Highlights: • The elemental core–shell heterostructure was reported for the first time. • The hydrophilic core–shell S/In₂O₃ photocatalyst was prepared by ball milling. • The rate constant of 10% S/In₂O₃ is 11.6 and 13.5 times that of In₂O₃ and S. • The hydrophilicity and efficiently separation of carriers are major factor. - Abstract: Recently, elemental semiconductors as new photocatalysts excited by visible light have attracted great attention due to their potential applications for environmental remediation and clean energy generation. However, it is still a challenge to fabricate elemental photocatalysts with high activity and stability. In this paper, a straightforward ball-milling method was carried out to fabricate core–shell S/In₂O₃ nanocomposite photocatalyst with high performance. The photocatalyst was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectroscopy (DRS), Brunauer–Emmett–Teller (BET) method, photoluminescence spectra (PL) and super-hydrophilic experiment. The results showed that In₂O₃ nanoparticles were successfully grown round of S blocks and formed core–shell heterostructures. The 10% S/In₂O₃ core–shell nanocomposite exhibited the highest photocatalytic activity for degradation of rhodamine B (RhB) under visible light irradiation. The reaction rate constant (k) of the 10% S/In₂O₃ core–shell nanocomposite is about 8.7 times as high as the sum of pure In₂O₃ and S because of the formation of core–shell S/In₂O₃ heterostructures, which might remedy the drawbacks of poor hydrophilicity of S, enhance visible light absorption and separate the photogenerated carriers efficiently. Furthermore, the mechanism of influence on the photocatalytic activity of the S/In₂O₃ core–shell nanocomposite was also discussed. It is anticipated that our work may open up a new direction for the fabrication of core–shell heterostructure to remedy the drawbacks of a photocatalyst and expand its application in the field of photocatalysis