One-pot preparation of porous Cr₂O₃/g-C₃N₄ composites towards enhanced photocatalytic H₂ evolution under visible-light irradiation

Porous Cr₂O₃/g-C₃N₄ composites were prepared by a facile one-pot pyrolysis method and showed enhanced visible-light-driven photocatalytic H₂-evolution activities, with the highest rate 4.0 times of that for pure g-C₃N₄. During the one-pot process, accompanied by the pyrolysis of melamine to form g-C₃N₄, CrCl₃·6H₂O acted as Cr precursor to form Cr₂O₃, and meanwhile functioned as pore-forming agent to increase the surface area and pore volume of g-C₃N₄. The cocatalytic effect of Cr₂O₃ and the favorable textural properties of g-C₃N₄ promoted the separation of photogenerated charge carriers, facilitated the diffusion, accumulation and adsorption of reactants, enriched the reactive sites for redox reaction, and thus resulted in the enhanced photocatalytic activities. This work presented an effective route to simultaneously optimize the compositions and micro/nano-structures of photocatalysts for H₂ evolution.