超细硫化钼纳米线的电子结构和催化析氢性能的第一性原理研究（英文）

First-Principles Study of Ultrathin Molybdenum Sulfides Nanowires:Electronic and Catalytic Hydrogen Evolution Properties

本文基于第一原理计算研究了一类新的1D超细硫化钼纳米线,包括Mo2S6、Mo3S6和Mo6S10纳米线.通过声子谱计算和600 K下的波恩-奥本海默分子动力学模拟,结果表明这些超细纳米线具有晶格动力学稳定性和较高的热稳定性.计算所得Mo2S6、Mo3S6和Mo6S10纳米线的弹性常数分别为21.33、103.22和163.00 eV/■.其中Mo2S6,Mo3S6纳米线是带隙为1.55和0.46 eV的半导体,而Mo6S10纳米线则表现为金属.另外,这些超细硫化钼纳米线可以作为催化剂用于析氢反应.对于Mo2S6纳米线,其氢吸附自由能变约为-0.05 eV,这与Pt和H-MoS2的氢吸附自由能变相当.这些1D硫化钼纳米线的预测可以丰富1D硫化钼家族,同时为理解过渡金属硫化物在析氢反应上的高效性能作为补充.

Molybdenum sulfides nanomaterials, such as one-dimensional (1D) nanotubes, nanoribbons, and two-dimensional (2D) nanosheets, have attracted intensive research interests for their novel electronic, optical, and catalytic properties. On the basis of first-principles calculation, here, we report a new series of 1D ultrathin molybdenum sulfides nanowires, including Mo2S6、Mo3S6 and Mo6S10 nanowires. Our results demonstrate that these ultrathin nanowires are both thermal and lattices dynamically stable, confirmed with the calculated phonon spectrum and Born-Oppenheimer molecular dynamic simulation at the temperature up to 600 K. The calculated elastic constant is 21.33, 103.22, and 163.00 eV/■ for Mo2S6, Mo3S6, and Mo6S10 nanowires, respectively. Mo2S6 and Mo3S6 nanowires are semiconductors with band gap of 1.55 and 0.46 eV, while Mo6S10 nanowires is metal, implying their potential applications in electronics and optoelectronics. In particular, ultrathin molybdenum sulfides nanowires can be used as catalysts for hydrogen evolution reaction. The calculated Gibbs free energy change for hydrogen evolution is about -0.05 eV for Mo2S6 nanowire, comparable with those of Pt and H-MoS2. The prediction of these 1D molybdenum sulfides nanowires may enrich the 1D family molybdenum sulfides and make a supplement to understand the high performance of hydrogen evolution reaction in transition-metal dichalcogenides.