Photocatalytic Activity of Heterostructures Based on Graphite-Like Carbon Nitride Modified with Few-Layer Black Phosphorus and Cobalt Phosphide in the Hydrogen Evolution Reaction

The photocatalytic activity of 2D/2D/0D heterostructures based on few-layer black phosphorus (FLBP) g-C₃N₄/FLBP/Co₂P in the reaction of photocatalytic hydrogen formation from an aqueous solution of triethanolamine under under visible light irradiation (400 nm) was studied for the first time. An original method for the preparation of the g‑C₃N₄/FLBP/Co₂P composite photocatalyst is proposed, which consists of the solvothermal synthesis of cobalt phosphide Co₂P nanoparticles, their immobilization on the surface of FLBP, and subsequent mixing of the FLBP/Co₂P heterostructure with g‑C₃N₄. The synthesized photocatalysts were characterized by physicochemical analytical methods (X-ray diffraction, X-ray photoelectron spectroscopy, high-resolution transmission microscopy, energy-dispersive X-ray spectroscopy). The hydrogen evolution rate in the presence of the g‑C₃N₄/FLBP/Co₂P heterostructure was 0.09 mmol \({\text{g}}_{{{\text{cat}}}}^{{ - 1}}\) h^–1, which is 25 times higher than the same characteristic for the unmodified g‑C₃N₄ sample. The obtained numerical values of the photocatalytic activity are at the level of the literature values.