“Feather-duster” like ZnIn2S4/TiO2 heterostructured nanocomposites with enhanced visible-light photocatalytic performance

Abstract

ZnIn₂S₄/TiO₂ nanocomposites were prepared by solvothermal growth of ultrathin ZnIn₂S₄ nanosheets uniformly on TiO₂ nanowires and were demonstrated as efficient chromium(VI) reduction catalysts under visible-light irradiation. The ZnIn₂S₄ nanosheets were uniformly coated on TiO₂ nanowires. The Cr(VI) removal efficiency followed the order: 0.5ZnIn₂S₄/TiO₂ (98.57%) > 1ZnIn₂S₄/TiO₂ (98.20%) > 1.5ZnIn₂S₄/TiO₂ (91.13%) > 0.25ZnIn₂S₄/TiO₂ (68.50%) > ZnIn₂S₄ (56.8%) after 120 min of light irradiation. The high catalytic performance can be ascribed to the enhanced light absorption, larger specific area, and higher electron–hole separation rate. Owing to the narrower band gap (∼2.7 eV), strong visible-light response, and high recombination rate of photogenerated carriers of ZnIn₂S₄, some modification must be taken to separate the photogenerated electron–hole pairs effectively. Although TiO₂ nanowires are only UV responsive, the ZnIn₂S₄/TiO₂ nanocomposite, with an increased surface area and strengthened interface contact with each other, facilitates efficient photogenerated carrier separation and leads to high photocatalytic performance under visible light irradiation. The work provides an excellent strategy for the rational design of heterostructured nanocomposite photocatalysts.