c-Ni3S2/r-Ni3S2同质异相结的原位构筑及电催化析氢性能研究

碱性条件下电解水是大规模制备氢气的有效途径之一。廉价的Ni3S2在碱性条件下表现出良好的析氢性能，但仍存在一些问题：Ni位点对水分子的离解能力不足，S位点对活性氢的吸附能力不足，阻碍其性能进一步提升。界面设计是改善材料电子结构、提高催化活性的重要手段。Ni3S2存在低温菱方相(r-Ni3S2)和高温立方相(c-Ni3S2)。本项目拟在泡沫镍上原位构筑c-Ni3S2/r-Ni3S2同质异相结界面，并在硫位点掺杂硒、碲原子，提高Ni3S2的析氢活性。一方面，本异相结界面的构筑可以降低Ni位点电子密度、减弱Ni离子感受到的晶体场，从而增强Ni位点对水分子的离解能力。另一方面，硒、碲原子掺杂可以抬升S位点外层p轨道，增强与氢s轨道的重叠，提高对活性氢的吸附能力。本项目的实施不仅可以推动Ni3S2在电解水制氢方面的应用，而且可以为新型同质异相结材料的设计提供参考和依据，解决一些共性科学问题。

Electrical water splitting in alkaline is one of the effective ways to produce hydrogen on a large scale. Ni3S2 exhibits high activity for hydrogen evolution reaction (HER) in alkaline. However, there are still unsolved problems for Ni3S2, which hinders further improvement of its performance. For example, the dissociation capacity of Ni sites for water molecules is insufficient and S sites lack adsorption ability for active hydrogen. Interface design is an important method to improve the electronic structure of materials and increase the catalytic activity. Ni3S2 has a low-temperature rhombohedral phase (r-Ni3S2) and a high-temperature cubic phase (c-Ni3S2). To improve the HER activity of Ni3S2, this project intends to construct the c-Ni3S2/r-Ni3S2 homogeneous phase junction in situ on nickel foam, and dope selenium and tellurium atoms at the sulfur site. On the one hand, the construction of c-Ni3S2/r-Ni3S2 can reduce the electron density of Ni sites and weaken the crystal field felt by Ni ions, thereby enhancing the ability of Ni sites to dissociate water molecules. On the other hand, doping with selenium and tellurium atoms can raise the p-orbital in the outer layer of the S sites, enhance the overlap with the hydrogen s-orbital, and improve the adsorption capacity of active hydrogen. The implementation of this project can not only promote the application of Ni3S2 in the electrolysis of water for hydrogen production, but also provide reference and basis for the design of new phase junction materials, and solve some common scientific problems.