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

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.