Recently, to enhance the catalytic activity of molybdenum carbide (Mo₂C) electrocatalysts for the hydrogen evolution reaction (HER), the conductive carbon-based materials with different structures have been used to support Mo₂C particles for providing sufficient catalytic hydrogen production sites. Nevertheless, it is always hard to use a simple method to ensure both uniform distribution of Mo₂C particles and good charge transfer between Mo₂C and carbon matrix. Herein, we used a low-cost carbonaceous material as ingredient via a facile method of in situ carbonization to design the structure of Mo₂C nanoparticles embedded in chainlike Ketjenblack carbon (KB) with strong chemical link, to achieve the Mo₂C/KB hybrid catalyst with uniform distribution of active Mo₂C nanocrystals on KB for high density of catalytic sites and excellent charge-transfer ability. Moreover, the effects of carbonization temperature and carbon content on the HER activity were investigated to optimize the Mo₂C/KB catalyst. The optimized Mo₂C/KB catalyst exhibits outstanding HER activity in both acidic and alkaline media with small Tafel slopes of 49 and 48 mV dec^–1, low overpotentials, and remarkable stability. The enhanced HER activity of Mo₂C/KB catalyst could be ascribed to its unique chainlike structure with a large specific surface area of 580.3 m² g^–1, the high electronic conductivity, and active Mo₂C nanocrystals protected by robust carbon matrix.

中文翻译：

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原位制备嵌在科琴黑炭中的Mo ₂ C纳米颗粒作为高效的氢析出电催化剂

近来，为了增强碳化钼（Mo ₂ C）电催化剂对氢析出反应（HER）的催化活性，具有不同结构的导电碳基材料已被用于负载Mo ₂ C颗粒以提供足够的催化氢产生位点。然而，始终难以使用简单的方法来确保Mo ₂ C颗粒的均匀分布以及Mo ₂ C与碳基体之间的良好电荷转移。在这里，我们通过一种廉价的碳质材料，通过一种简便的原位碳化方法，设计了嵌入化学键很强的链状科琴黑碳（KB）中的Mo ₂ C纳米粒子的结构，从而实现了Mo₂ C / KB杂化催化剂，活性Mo ₂ C纳米晶体在KB上均匀分布，具有高催化位密度和出色的电荷转移能力。此外，研究了碳化温度和碳含量对HER活性的影响，以优化Mo ₂ C / KB催化剂。经过优化的Mo ₂ C / KB催化剂在酸性和碱性介质中均具有出色的HER活性，Tafel斜率为49和48 mV dec ^-1小，超低电势，并且具有显着的稳定性。Mo ₂ C / KB催化剂的增强的HER活性可以归因于其独特的链状结构，其大比表面积为580.3 m ² g ^–1，高电子电导率和受稳固碳基质保护的活性Mo ₂ C纳米晶体。