Zinc Vanadate (Zn 3 V 2 O 8 ) Immobilized Multiwall Carbon Nanotube (MWCNT) Heterojunction as an Efficient Photocatalyst for Visible Light Driven Hydrogen Production.

Z-scheme photocatalytic reaction is considered an effective strategy to promote the photogenerated electron-hole separation for significantly improving the efficiency of photocatalytic hydrogen precipitation from splitting water. In this study, a heterojunction nanocomposite material based on Zn 3 V 2 O 8 (ZV) with MWCNT was prepared by a hydrothermal process. The photocatalysts were characterized by X-ray diffraction, scanning electron microscopy (SEM), Fourier transform infrared (FTIR), UV-visible absorption spectroscopy, and transmission electron microscopy (TEM) to understand crystal structure, morphology, and optical properties. The efficiency of the samples was evaluated for the photocatalytic H 2 production under visible solar radiation using water glycerol as a sacrificial reagent. The obtained results suggest that, between ZV and ZV@MWCNT, the latter shows higher efficiency for H 2 production. The maximum H 2 production efficiency was found to be 26.87 μmol g -1 h -1 for ZV and 99.55 μmol g -1 h -1 for ZV@MWCNT. The synergistic effect of MWCNT to ZV resulted in improving the efficiency of charges and light-absorbing capacity, resulting in enhanced H 2 production in the heterojunction nanocomposite material. The nanocomposite was stable and highly efficient for H 2 production of six or more cycles. Based on the outcomes of this study, it can be observed that forming the heterojunction of individual nano systems could result in more efficient material for H 2 production under visible solar energy.