Fabrication of graphitic carbon Nitride/Nonstoichiometric molybdenum oxide nanorod composite with the nonmetal plasma enhanced photocatalytic hydrogen evolution activity

The extended light absorption and the prevented charge recombination are crucial for the graphitic carbon nitride (g-C3N4) based photocatalytic materials. Herein, nonstoichiometric molybdenum oxide (MoO3-x) nanorods with oxygen vacancies were synthesized by a hydrothermal method with trace amount of oleylamine, and the Z-scheme two-dimentional (2D)/one-dimentional (1D) g-C3N4/MoO3-x composites were prepared by a facile electrostatic assembling approach. The blue MoO3-x nanorods with oxygen vacancies are loaded uniformly on the g-C3N4 nanosheets. The g-C3N4/MoO3-x composite materials exhibit strong absorption in the visible and near-infrared light regions, and the improved charge separation efficiency through the Z-scheme charge transfer mechanism. The g-C3N4/MoO3-x composite presents a significantly improved photocatalytic hydrogen generation activity with good cycling stability compared with sonicated g-C3N4 nanosheets. The best hydrogen generation activity of 209.2 μmol·h-1 under solar light irradiation and the highest apparent quantum efficiency of 4.4% irradiated at 365 nm are obtained by the g-C3N4/MoO3-x composite with a mass percent of 27.5%, which is 2.63 times of g-C3N4. The weight ratios and the content of oxygen vacancies in the small-size MoO3-x nanorods have a significant influence on the photocatalytic hydrogen performance. Moreover, effective photocatalytic overall water splitting can be achieved with the H2 and O2 evolution rates of 0.755 and 0.368 μmol∙h-1 by the g-C3N4/MoO3-x composite. The novel g-C3N4/MoO3-x composite will have broad prospects in the field of photocatalytic applications.