Gao Nan, Yang Xiaowei, Chen Jinghuang, Chen Xinru, Li Jiadong, Fan Junyu
School of Materials Science and Engineering, Taizhou University, Taizhou, 318000, China.
Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116024, China.
Phys Chem Chem Phys. 2023 Feb 1;25(5):4297-4304. doi: 10.1039/d2cp05471j.
Monolayer transition metal dichalcogenides (TMDs), typical two-dimensional semiconductors, have been extensively studied for their extraordinary physical properties and utilized for nanoelectronics and optoelectronics. However, the finite samples and discontinuity in the synthesis process of TMD materials definitely induce defect edges in nanoribbons and greatly influence the device performance. Here, we systematically studied the atomic structures, energetic and mechanical stability, and electronic and catalytic properties of MoSe nanoribbons on the basis of experiments. Clear benefits of ZZSe-Mo-NW30 edged nanoribbons were found to evidently increase the dynamic stability according to our first-principles calculations. Meanwhile, unsaturated Mo atoms at the edge sites induced local magnetic moments up to 0.54 and changed the chemical environments of adjacent Se atoms, which acted as active sites for the hydrogen evolution reaction (HER) with a lower onset potential of -0.04 eV. The external tensile strain on these nanoribbons can have negligible effects on the electronic and catalytic properties. The onset potential of the ZZSe-Mo-NW30 edged nanoribbons only changed 0.03 eV under critical tensile strain. The atomic-scale research of edge reconstructions in TMD materials provides new opportunities to modulate the synthesis mechanism for experiments and defect-engineering applications in electrochemical catalysts.
单层过渡金属二硫属化物（TMDs）作为典型的二维半导体，因其非凡的物理性质而受到广泛研究，并被应用于纳米电子学和光电子学领域。然而，TMD材料在合成过程中的有限样品和不连续性必然会在纳米带中引入缺陷边缘，从而极大地影响器件性能。在此，我们在实验的基础上系统地研究了MoSe纳米带的原子结构、能量和力学稳定性以及电子和催化性能。根据我们的第一性原理计算，发现ZZSe-Mo-NW30边缘纳米带具有明显优势，能显著提高动态稳定性。同时，边缘位置的不饱和Mo原子诱导出高达0.54的局部磁矩，并改变了相邻Se原子的化学环境，这些Se原子作为析氢反应（HER）的活性位点，起始电位低至-0.04 eV。这些纳米带上的外部拉伸应变对其电子和催化性能的影响可忽略不计。在临界拉伸应变下，ZZSe-Mo-NW30边缘纳米带的起始电位仅变化了0.03 eV。对TMD材料边缘重构的原子尺度研究为调控实验合成机制以及电化学催化剂中的缺陷工程应用提供了新的机遇。
