Enhanced Photocatalytic Hydrogen Production of the Polyoxoniobate Modified with RGO and PPy

The development of high-efficiency, recyclable, and inexpensive photocatalysts for water splitting for hydrogen production is of great significance to the application of solar energy. Herein, a series of graphene-decorated polyoxoniobate photocatalysts Nb₆/PPy-RGO (Nb₆ = K₇Nb₆O₁₉, RGO = reduced graphene oxide, PPy = polypyrrole), with the bridging effect of polypyrrole were prepared through a simple one-step solvothermal method, which is the first example of polyoxoniobate-graphene-based nanocomposites. The as-fabricated photocatalyst showed a photocatalytic H₂ evolution activity without any co-catalyst. The rate of 1038 µmol g^-1 in 5 h under optimal condition is almost 43 times higher than that of pure K₇HNb₆O₁₉·13H₂O. The influencing factors for photocatalysts in photocatalytic hydrogen production under simulated sunlight were studied in detail and the feasible mechanism is presented in this paper. These results demonstrate that Nb₆O₁₉ acts as the main catalyst and electron donor, RGO provides active sites, and PPy acted as an electronic bridge to extend the lifetime of photo-generated carriers, which are crucial factors for photocatalytic H₂ production.