Collaborative Innovation Center of Chemistry for Energy Material, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Key Laboratory of Computational Physical Science, Department of Chemistry, Fudan University , Shanghai 200433, China.
Key Laboratory for Microstructures, School of Materials Science and Engineering, Shanghai University , Shanghai 200072, China.
J Am Chem Soc. 2017 Feb 22;139(7):2545-2548. doi: 10.1021/jacs.6b11193. Epub 2017 Feb 9.
Under mild static compression (15 GPa), graphite preferentially turns into hexagonal diamond, not cubic diamond, the selectivity of which is against thermodynamics. Here we, via novel potential energy surface global exploration, report seven types low energy intermediate structures at the atomic level that are key to the kinetics of graphite to diamond solid phase transition. On the basis of quantitative kinetics data, we show that hexagonal diamond has a facile initial nucleation mechanism inside graphite matrix and faster propagation kinetics owing to the presence of three coherent graphite/hexagonal diamond interfaces, forming coherent nuclei in graphite matrix. By contrast, for the lack of coherent nucleus core, the growth of cubic diamond is at least 40 times slower and its growth is inevitably mixing with that of hexagonal diamond.
在轻度静态压缩（15GPa）下，石墨优先转化为六方金刚石，而非立方金刚石，这种选择性违反热力学。在这里，我们通过新颖的势能面全局探测，在原子水平上报告了七种类型的低能中间结构，这些结构是石墨到金刚石固相转变动力学的关键。基于定量动力学数据，我们表明，六方金刚石在石墨基体中具有易于初始成核的机制，并且由于存在三个相干的石墨/六方金刚石界面，从而具有更快的传播动力学，在石墨基体中形成相干核。相比之下，由于缺乏相干核芯，立方金刚石的生长速度至少慢 40 倍，其生长不可避免地与六方金刚石的生长混合。
