Lu Linguo, Yu Shansheng, Tian Hongwei
Key Laboratory of Automobile Materials of MOE and Department of Materials Science, Jilin University, Changchun 130012, China.
Key Laboratory of Automobile Materials of MOE and Department of Materials Science, Jilin University, Changchun 130012, China.
J Colloid Interface Sci. 2022 Feb;607(Pt 1):645-654. doi: 10.1016/j.jcis.2021.09.020. Epub 2021 Sep 11.
Pentlandite (Fe,Ni)S is a promising transition-metal catalyst for the hydrogen evolution reaction. However, little is explained about the long activation process that has been observed in experiments, and its facet-dependent hydrogen evolution activity is still theoretically unrevealed. To explain some experimental phenomena and to guide subsequent studies, density functional theory calculations are used to study the main synthetic surfaces: (111) and (311) in this work. The results show that the small metal cube plays an important role in the surface stability, and it is suggested that such cubes remain intact during catalysis. The linking sites serve as a bridge across the metal cubes and are the main catalytic active sites for hydrogen evolution. This is because the metal cubes can tune the electronic structures of the linking sites, and then the free energy of the linking sites is optimized. The (311) surface is a composite surface that consists of (100) and (111) facets and has the profile of a step. A surface conversion between the (311) and (111) facets may occur when the cube layer length increases. Therefore, the active sites can be feasibly engineered by the surface structures, and this could be helpful in further applications of (Fe,Ni)S.
镍黄铁矿（Fe,Ni）S是一种很有前景的用于析氢反应的过渡金属催化剂。然而，关于实验中观察到的漫长活化过程，目前解释甚少，而且其面依赖的析氢活性在理论上仍未揭示。为了解释一些实验现象并指导后续研究，本文采用密度泛函理论计算来研究主要的合成表面：（111）面和（311）面。结果表明，小金属立方体在表面稳定性中起重要作用，并且表明这些立方体在催化过程中保持完整。连接位点充当跨越金属立方体的桥梁，是析氢的主要催化活性位点。这是因为金属立方体可以调节连接位点的电子结构，进而优化连接位点的自由能。（311）面是由（100）面和（111）面组成的复合表面，具有台阶状轮廓。当立方体层长度增加时，（311）面和（111）面之间可能会发生表面转变。因此，可以通过表面结构切实地设计活性位点，这可能有助于（Fe,Ni）S的进一步应用。
