二维M_(2)X_(2)(M:Mo、W和X:F、Cl)析氢和析氧反应的电催化性能

Electrocatalytic properties of two-dimensional M_(2)X_(2)(M:Mo、W and X:F、Cl)for hydrogen and oxygen evolution reactions

以剥离密排六方结构(HCP)的块状金属,形成单层金属薄膜为切入点,通过用卤素原子钝化中间金属层的方法,形成了一类稳定的ABAB堆叠的金属卤素化合物.对比了*O中吸附O原子和不吸附O原子的Mo-d投影态密度图,期望揭示电子排布、成键状态与材料催化性能之间的关联.电子结构计算表明Mo_(2)X_(2)和W_(2)X_(2)具有很好的导电性.通过与过渡金属二硫化物(MoS 2)类比,将缺陷工程(卤素原子空位)引入活性位点,然后计算了其在四电子转移析氧反应中的反应能垒,发现它们具有良好的催化性能,其中,W 2Cl 2的析氧催化性能最好,过电位仅有1.95 V.最后,通过详细分析电子、轨道之间耦合作用,给出了清晰的物理图像.

Starting from stripping the bulk metal of the hexagonal close-packed(HCP)crystal structure and forming a single-layer metal film,a stable ABAB-stacked metal halide compound was formed by passivating the intermediate metal layer with halogen atoms.The Mo-d projected density of states of adsorbed O atoms and non-adsorbed O atoms in*O are compared,and it is expected to reveal the relationship between electron arrangement,bonding state and catalytic performance of materials.Electronic structure calculations show that Mo_(2)X_(2)and W_(2)X_(2)have good electrical conductivity.By analogy with transition metal disulfides(MoS 2),defect engineering(halogen atom vacancies)is introduced into active sites,and then their reaction energy barriers in the four-electron transfer oxygen evolution reaction are calculated.It is found that they have good catalytic performance.Among them,W 2Cl 2 has the best oxygen evolution catalytic performance,and the overpotential is only 1.95 V.Finally,a clear physical image is given by analyzing the coupling between electrons and orbits in detail.