Construction of noble-metal-free TiO₂ nanobelt/ZnIn₂S₄ nanosheet heterojunction nanocomposite for highly efficient photocatalytic hydrogen evolution

Abstract

A binary nanocomposite composed of two-dimensional (2D) ultrathin ZnIn₂S₄ nanosheets and one-dimension (1D) TiO₂ nanobelts was prepared and applied as a noble-metal-free photocatalyst for hydrogen evolution under solar-light irradiation. The TiO₂ nanobelt/ZnIn₂S₄ nanosheet heterojunction nanocomposites show higher light absorption capacity, larger surface area and higher separation of charge carriers in comparison to pristine TiO₂ and ZnIn₂S₄. As a result, the hydrogen production over the TiO₂/ZnIn₂S₄ nanocomposite with 15 wt% TiO₂ can reach up to 348.21 μmol · g^-1 · h^-1, even without noble metals, which is about 26 and 2.3 times higher than the pristine TiO₂ and ZnIn₂S₄, respectively. Meanwhile, a possible photocatalytic mechanism of TiO₂/ZnIn₂S₄ heterojunction nanocomposites was proposed and corroborated by photoluminescence (PL) spectroscopy and photoelectrochemical (PEC) results. This work paves a way for developing low-cost and high-efficiency noble-metal-free photocatalytic systems for solar-to-hydrogen evolution.