The production of hydrogen via electrochemical water splitting has the potential to enable the utilization of hydrogen-powered fuel cells on a large scale. However, to realize this technology, inexpensive, noble metal-free electrocatalysts possessing high performances for the hydrogen evolution reaction (HER) are needed. Mo₂C nanoparticles recently receive much attention as alternative noble metal-free electrocatalysts because their electronic structures are akin to that of Pt. However, the synthesis of Mo₂C at nanoscale with high catalytic activity for HER remains a great challenge. Moreover, although efforts have been made to prevent their aggregation, the particles coalesce during high temperature carbonization, which is typically used to produce such transition metal carbides. Here, the synthesis of Mo₂C nanodots that are well-dispersed within 3D cage-like carbon microparticles using rationally designed Mo-based xerogels, which are prepared via the sol–gel process as precursors, is reported. During their pyrolysis, the xerogels maintain their structures while the Mo species in them transform into well-dispersed Mo₂C nanodots in situ. The as-synthesized Mo₂C nanodots exhibit excellent electrocatalytic activity for HER, in both alkaline and acidic media, while remaining largely stable. The work also demonstrates a promising synthetic route and procedure to other well-dispersed yet stable nanocatalysts.

中文翻译：

---

来自 Mo 基干凝胶的碳纳米笼中高度分散的 Mo2C 纳米点：用于析氢的高效电催化剂

通过电化学水分解生产氢气有可能使氢动力燃料电池的大规模利用成为可能。然而，为了实现这项技术，需要具有高性能析氢反应（HER）的廉价、不含贵金属的电催化剂。Mo ₂ C 纳米粒子最近作为替代的无贵金属电催化剂备受关注，因为它们的电子结构类似于 Pt 的电子结构。然而，Mo ₂的合成对 HER 具有高催化活性的纳米级 C 仍然是一个巨大的挑战。此外，尽管已努力防止它们的聚集，但颗粒在高温碳化过程中会聚结，高温碳化通常用于生产此类过渡金属碳化物。在这里，报道了使用合理设计的 Mo 基干凝胶合成良好分散在 3D 笼状碳微粒中的 Mo ₂ C 纳米点，该干凝胶是通过溶胶-凝胶工艺制备的作为前体。在热解过程中，干凝胶保持其结构，而其中的 Mo 物种原位转化为分散良好的 Mo ₂ C 纳米点。合成的 Mo ₂C 纳米点在碱性和酸性介质中都表现出优异的 HER 电催化活性，同时保持基本稳定。该工作还展示了其他分散良好但稳定的纳米催化剂的有前途的合成路线和程序。