First-Principles Study of the Atomic Structures and Catalytic Properties of Monolayer TaS2 with Intrinsic Defects
First-Principles Study of the Atomic Structures and Catalytic Properties of Monolayer TaS2 with Intrinsic Defects
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具有本征缺陷的单层TaS2原子结构和催化性能的第一性原理研究
DOI：
10.1021/acs.jpcc.1c01667
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发表时间：
2021-05-12
影响因子：
3.7
通讯作者：
Chen, Yue
中科院分区：
文献类型：
--
作者：
Gao, Nan;Liang, Xiaoqing;Chen, Yue
单层二硫化钽(TaS_2)因其超导和电荷密度波(CDW)特性而备受关注。然而，在制作的样品中经常会观察到多个结构缺陷，这极大地影响了它们的性能。利用第一性原理计算方法，系统地研究了TaS_2单层的6个公共点缺陷和6个晶界的原子结构、能量稳定性、电子性质和催化性质。单分子层TaS_2的单S原子空位缺陷在2 eV以下具有最低的形成能，与化学环境无关。对于GBs，4个垂直的4个和4个垂直的8个无同元素键的缺陷环比5个垂直的7个缺陷环更容易形成。对于析氢反应(HER)过程，不同缺陷位的结合强度分别与S或Ta原子的p带或d带中心有关。特别是具有单个S空位缺陷的TaS_2催化剂表现出优异的催化活性，H原子的吸附能为0.1 eV，Tafel势垒为0.25 eV。这些理论结果为在实验中检测二维TaS_2的各种缺陷以及通过缺陷工程来调节催化性能提供了重要的指导。
Monolayer tantalum disulfide (TaS2) has attracted much attention for its superconducting and charge-density-wave (CDW) properties. However, multiple structural defects are frequently observed in fabricated samples and greatly influence their performance. Using first-principles calculations, we systematically investigate the atomic structures, energetic stability, and electronic and catalytic properties of six common point defects and six grain boundaries (GBs) of the monolayer TaS2. The single S atom vacancy defect of the monolayer TaS2 has the lowest formation energy below 2 eV, regardless of the chemical environment. For GBs, 4 vertical bar 4 and 4 vertical bar 8 defect rings without homoelemental bonds are predicted to form more easily than the 5 vertical bar 7 defect ring. For the hydrogen evolution reaction (HER) process, the binding strengths of different defect sites are related to the p- or d-band center of the S or Ta atom, respectively. In particular, TaS2 with a single S vacancy defect shows superior catalytic activity with a H atom adsorption energy of 0.1 eV and a Tafel barrier of 0.25 eV. These theoretical results provide vital guidance for detecting various defects of two-dimensional TaS2 in experiments and modulating catalytic properties via defect engineering.