Synthesis of vanadium-pentoxide-supported graphitic carbon nitride heterostructure and studied their hydrogen evolution activity under solar light

Abstract

Noble-metal-free co-catalyst supported with a highly active and stable photocatalyst is of considerable importance to realize low cost and scaled up photocatalytic hydrogen evolution. An inorganic–organic two-dimensional (2D)/one-dimensional (1D) graphitic carbon nitride (g-C3N4) nanosheet anchored with a vanadium pentoxide (V2O5) nanoparticle heterojunction photocatalyst (GCN/V2O5-3) with excellent solar-light-driven photocatalytic performance was prepared using a facile thermal decomposition method and used for photocatalytic hydrogen (H2) evolution from concentrated lactic acid aqueous solution. The optimized GCN/V2O5-3 catalyst attained a high initial H2 evolution rate of 2891.53 µmol g−1, which is 2.44 times greater than that of pristine g-C3N4 under simulated solar light irradiation. In addition, the GCN/V2O5-3 catalyst is relatively stable for 5 h H2 evolution reactions, indicating the robustness of the V2O5 co-catalyst. The improved photocatalytic activity of the g-C3N4/V2O5 composites can be ascribed to their large specific surface area. Photoelectrochemical analysis results clearly show that V2O5 co-catalyst captures photoinduced holes from the valance band of the excited g-C3N4 by a Z-scheme mechanism and thus improving the charge separation performance and endorse the H+ reduction to H2. Lastly, the mechanism of photocatalytic H2 evolution of the g-C3N4/V2O5 composite is discussed. Importantly, because of its high stability, easy processing, and low cost, the V2O5 co-catalyst has abundant potential in designing high-performance-semiconductor/organic photocatalysts for large-scale H2 production utilizing renewable energy sources.