MXenes, a novel class of 2D transition metal carbides and nitrides, have recently emerged as a promising candidate in the quest for efficient catalysts for the hydrogen evolution reaction. To enhance the performance of 2D MXenes with modest or poor catalytic efficiency, a particularly prosperous strategy involves doping with transition and noble metal atoms. Taking the Nb₄C₃O₂ monolayer as a model, we explore substitutional metallic impurities, which serve as single-atom catalysts embedded within the Nb₄C₃O₂ surface. Our findings demonstrate the ability to finely tune the atomic H binding energy within a 0.6 eV range, showing the potential for precise control in catalytic applications. Across different transition and noble metals, the single atoms integrated into Nb₄C₃O₂ effectively adjust the free energy of H adsorption at nearby O atoms, achieving values comparable to or superior to Pt catalysts. A comprehensive examination of the electronic properties around the impurities reveals a correlation between changes in local reactivity and charge transfer to neighboring O atoms, where H atoms bind.

MXenes 是一类新型的二维过渡金属碳化物和氮化物，最近成为寻找高效析氢反应催化剂的有希望的候选者。为了以中等或较差的催化效率提高 2D MXene 的性能，一种特别有效的策略是掺杂过渡金属和贵金属原子。以Nb ₄ C ₃ O ₂单层为模型，我们探索了替代金属杂质，它们作为嵌入Nb ₄ C ₃ O ₂表面的单原子催化剂。我们的研究结果表明能够在 0.6 eV 范围内微调原子 H 结合能，显示出在催化应用中精确控制的潜力。在不同的过渡金属和贵金属中，集成到Nb ₄ C ₃ O ₂中的单原子有效地调节了附近O原子的H吸附自由能，达到了与Pt催化剂相当或优于Pt催化剂的值。对杂质周围电子特性的全面检查揭示了局部反应性变化和电荷转移到邻近的 O 原子（H 原子在 O 原子上结合）之间的相关性。