Zhou Wenyu, Dong Lichun, Tan Luxi, Tang Qing
School of Chemistry and Chemical Engineering, Chongqing Key Laboratory of Theoretical and Computational Chemistry, Chongqing University, Chongqing 401331, People's Republic of China.
Nanotechnology. 2021 Apr 2;32(14):145718. doi: 10.1088/1361-6528/abd49f.
Defect engineering has been widely used in experiments to modulate the electrocatalytic properties of molybdenum disulfide (MoS). However, the effect of vacancy concentration on the vacancy distribution, electronic properties, and hydrogen evolution reaction (HER) activity remains elusive. Herein, we perform density functional theory (DFT) studies to investigate defective MoS with different numbers of sulfur vacancies. In the case of low S-vacancy concentration, the vacancies prefer to agglomerate rather than being dispersed, while at the higher-vacancy concentration, the combination of local point defect and clustered vacancy chain is preferred. The coupling between S-vacancies leads to decreased band gap and increased Mo-H adsorption strength with increasing vacancy concentration. The optimal HER activity is identified to occur below vacancy concentration of 12.50%. Our work provides an atomic-level understanding about the role of S-vacancies in the HER performance of MoS, and offers useful guidelines for the design of defective MoS and other TMDs electrocatalysts.
缺陷工程已在实验中广泛用于调节二硫化钼（MoS）的电催化性能。然而，空位浓度对空位分布、电子性质和析氢反应（HER）活性的影响仍然难以捉摸。在此，我们进行密度泛函理论（DFT）研究，以探究具有不同数量硫空位的缺陷MoS。在低硫空位浓度的情况下，空位倾向于聚集而不是分散，而在高空位浓度时，局部点缺陷和聚集的空位链的组合更受青睐。随着空位浓度的增加，硫空位之间的耦合导致带隙减小和Mo-H吸附强度增加。确定最佳HER活性出现在空位浓度低于12.50%时。我们的工作提供了关于硫空位在MoS的HER性能中作用的原子级理解，并为缺陷MoS和其他过渡金属二硫属化物电催化剂的设计提供了有用的指导。
