Developing low-cost and high-performance hydrogen evolution reaction (HER) electrocatalysts is a key research area for scalable hydrogen production from water electrolysis. Here, a hybrid of nitrogen-doped carbon encapsulated Mo₂C nanodots on Ti₃C₂T_x MXene (Mo₂C/Ti₃C₂T_x@NC) is developed through in situ polymerization of dopamine and a Mo precursor on the Ti₃C₂T_x MXene surface. During the annealing treatment, the polydopamine plays multiple roles in forming N-doped carbon, confining MoO₄²⁻ ions into ultrasmall Mo₂C nanodots, and stabilizing the MXene flakes against spontaneous oxidation. The as-synthesized hybrid exhibits excellent HER activity in acidic electrolyte with an overpotential of 53 mV at 10 mA cm⁻² and excellent stability over 30 hours. The combination of experiments and simulations demonstrates that pyridinic N-doped carbon coated Mo₂C nanodots serve as the active sites and Ti₃C₂T_x MXene facilitates the charge transfer, synergistically contributing to the superior HER performance.

中文翻译：

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MXenes上吡啶基N–Mo2C位点的有限生长，以释放氢

开发低成本和高性能的析氢反应（HER）电催化剂是水电解可扩展制氢的关键研究领域。在这里，通过多巴胺和Mo前驱体在Ti ₃ C ₂ T _x MXene（Mo ₂ C / Ti ₃ C ₂ T _x @NC）上的原位聚合，制得了氮掺杂的碳包封的Mo ₂ C纳米点杂化物。Ti ₃ C ₂ T _x MXene表面。在退火处理中，聚多巴胺在形成N掺杂碳，限制MoO ₄ ^{2-的过程中}起着多种作用。离子成超小的Mo ₂ C纳米点，并稳定MXene薄片免受自发氧化。合成后的杂化物在酸性电解质中表现出出色的HER活性，在10 mA cm ^-2下的过电势为53 mV，并且在30小时内具有出色的稳定性。实验和模拟的结合表明，吡啶鎓N掺杂的碳包覆的Mo ₂ C纳米点充当了活性位点，而Ti ₃ C ₂ T _x MXene促进了电荷转移，协同促进了卓越的HER性能。