In Situ Ni₂P-Integrated Black Phosphorus Nanosheets for Efficient Photocatalytic H₂ Evolution

The charge-carrier separation efficiency is one of the important factors for a high photocatalytic performance. Herein, a nickel phosphide (Ni2P) cocatalyst chemically bonded to black phosphorus (BP) nanosheets (0D/2D Ni2P/BP) has been synthesized by a facile one-step solvothermal process, using the commercial red phosphorus (RP) as a precursor material. RP is used not only to synthesize BP but also to form in situ Ni2P as a cocatalyst for the host BP photocatalyst. The in situ grown Ni2P on BP nanosheets leads to the creation of a Ni–P covalent bond, which enhances the charge separation as well as material stability. Thus, the developed nanocomposite was found to be efficient toward photocatalytic H2 production at a rate of 406.08 μmol·g–1·h–1 under sunlight with high apparent quantum yields of around 48.45 and 7.90% at 360 and 400 nm, respectively. Notably, the Ni2P/BP composite is found to be more efficient compared to the Pt/BP composite. As confirmed by the comparative study between the chemically and physically loaded Ni2P nanocomposites, the Ni–P bonds enhance the interfacial charge-carrier separation at the interface of BP and Ni2P, which ultimately increase the lifetime of the photogenerated electrons and improve the photocatalytic performance. The obtained results demonstrate that the established in situ one-step solvothermal synthesis strategy can be viable for the scalable synthesis of the developed materials for the large-scale H2 production under solar light.