Significantly enhanced charge transfer efficiency and surface reaction on NiP₂/g-C₃N₄ heterojunction for photocatalytic hydrogen evolution

In this work, a novel NiP₂/g-C₃N₄ heterojunction via homogeneous precipitation method assisted by thermal phosphorization reaction was designed and constructed, and the optimized sample showed the excellent photocatalytic H₂ evolution activity under visible-light irradiation, which was nearly 112 times higher than that of pristine g-C₃N₄ sample. Experimental characterizations and DFT calculations demonstrated that the NiP₂ nanoparticles covered on the g-C₃N₄ surface can form a built-in electric field at the interface to accelerate the transfer of photoexcited electrons from g-C₃N₄ to NiP₂, crucial for hindering the recombination of electron-hole pairs. Moreover, the energy barrier of hydrogen evolution reaction can also vastly reduce when combined NiP₂ and g-C₃N₄ to construct NiP₂/g-C₃N₄ heterojunction. This work represents a method through combing experimental and theoretical tools to thoroughly investigate the mechanism of photocatalytic process.