MX Anti-MXenes from Non-van der Waals Bulks for Electrochemical Applications: The Merit of Metallicity and Active Basal Plane
MX Anti-MXenes from Non-van der Waals Bulks for Electrochemical Applications: The Merit of Metallicity and Active Basal Plane
复制标题
DOI：
10.1021/acsnano.0c08429
复制
发表时间：
2021-03-18
期刊：
影响因子：
17.1
通讯作者：
Chen, Zhongfang
中科院分区：
文献类型：
--
作者：
Gu, Jinxing;Zhao, Ziyuan;Chen, Zhongfang
二维过渡金属化合物（2DTMCs）是一种很有前途的电化学材料，但具有金属性和活性基面的2DTMCs却很少。在这项工作中，我们提出了一种简单有效的策略，从非范德华体材料中提取2DTMC，并建立了79个2DTMC的材料库，我们称之为反MXene，因为它们由一个M原子层夹在两个X原子层之间组成。通过密度泛函理论计算，证实了24种antiMXenes在热力学、动力学、机械和热方面都是稳定的。金属性和活性基面赋予这些反MXene作为优良电极材料的潜力，例如，作为析氢反应（HER）的电催化剂。在具有有利的H结合的无贵金属的抗MXene中，CuS可以在整个H覆盖范围内提高HER，而CoSi、FeB、CoB和CoP在一些特定的H覆盖范围内显示出HER的前景。活性中心是在基面处的四配位非金属原子，从而使得这些材料具有非常高的活性中心密度。CoB也是一种有前途的锂离子电池负极材料，表现出低的Li扩散能垒、非常高的容量和合适的开路电压。这项工作促进了非范德华块体的2D材料的“计算剥离”，并证实了反MXene在各种电化学过程中的应用。
Two-dimensional transition-metal compounds (2DTMCs) are promising materials for electrochemical applications, but 2DTMCs with metallicity and active basal planes are rare. In this work, we proposed a simple and effective strategy to extract 2DTMCs from non-van der Waals bulk materials and established a material library of 79 2DTMCs, which we named as anti-MXenes since they are composed of one M atomic layer sandwiched by two X atomic layers. By means of density functional theory computations, 24 antiMXenes were confirmed to be thermodynamically, dynamically, mechanically, and thermally stable. The metallicity and active basal plane endow these anti-MXenes with potential as excellent electrode materials, for example, as electrocatalysts for hydrogen evolution reactions (HER). Among the noble-metal free anti-MXenes with favorable H-binding, CuS can boost HER at the whole range of H coverages, while CoSi, FeB, CoB, and CoP show promise for HER at some specific H coverages. The active sites are the tetra-coordinating nonmetal atoms at the basal planes, thus rendering a very high density of active sites for these materials. CoB is also a promising anode material for lithium-ion batteries, showing low Li diffusion energy barriers, a very high capacity, and a suitable open circuit voltage. This work promotes the "computational exfoliation" of 2D materials from non-van der Waals bulks and exemplifies the applications of anti-MXenes in various electrochemical processes.