▲?作者:Jiarui Fu, Takayuki Nakamuro, and Eiichi Nakamura
▲ 链接:
https://www.science.org/doi/10.1126/science.adw2025
▲ 摘要:
金刚石与金刚烷(Ad)虽具有相同的Td对称性碳骨架结构,但将金刚烷转化为金刚石一直面临挑战——该过程需实现碳氢(C–H)键的文导闻科选择性断裂并将单体组装成金刚石晶格。
我们的读新方法不同于传统的高温高压金刚石合成技术。通过在真空环境中以80—200千电子伏特电子束在100—296开尔文温度下辐照金刚烷亚微米晶体数十秒,学网我们成功制备出立方晶结构的科学无缺陷纳米金刚石(NDs),同时伴随氢气逸出。出版
时间分辨透射电子显微镜实时观测到金刚烷寡聚体初步形成并最终转变为球形纳米金刚石的周论WhatsApp%E3%80%90+86%2015855158769%E3%80%91cranes%20beach%20house%20delray过程。显著的文导闻科动力学同位素效应表明C–H键断裂是反应速控步骤,且其他测试碳氢化合物均未能形成纳米金刚石。读新
▲Abstract:
Diamond and 學(xué)網(wǎng)adamantane (Ad) share a?Td-symmetric carbon skeleton, but converting Ad to diamond has been challenging because it requires selective carbon-hydrogen (C–H) bond cleavage and monomer assembly into a diamond lattice. Our approach differs from the conventional high-temperature, high-pressure diamond syntheses. We electron-irradiated Ad submicrocrystals at 80 to 200 kilo–electron volts and 100 to 296 kelvin in vacuum for tens of seconds. This process yielded defect-free nanodiamonds (NDs) of cubic crystal structure, accompanied by hydrogen gas evolution. Time-resolved transmission electron microscopy revealed the initial formation of Ad oligomers transforming into spherical NDs. A sizable kinetic isotope effect indicates that C–H cleavage was rate-determining, and other hydrocarbons tested failed to form NDs.