Nanocatalysts are likely to contain undetected single-atom components, which may have been ignored but have significant effect in catalytic reactions. Herein, we report a catalyst composed of Mo single atoms (SAs) and MoO₂ nanoparticles (NPs) (Mo_SAs-MoO₂@NC), which is an exact model to understand how the SAs contribute to the nanocatalyst. Both experimental results and the density functional theory calculations reveal that Mo SAs on nitrogen-doped carbon provides the reaction zone for nitro reduction, while MoO₂ is the active site for decomposing hydrazine hydrate to produce H^⋆. Thanks to the synergy between Mo SAs and MoO₂ NPs, this catalyst exhibits noble metal-like catalytic activity (100% conversion at 4 min) for the dechlorination-proof transfer hydrogenation. Additionally, the hydrogen migration on the catalyst is verified by the electrochemical tests in the absence of a hydrogen source. This work provides a model for further study on the coexistence of single atoms in nanoparticle catalysts.

纳米催化剂可能包含未检测到的单原子成分，这些成分可能被忽略但在催化反应中具有重要影响。在此，我们报告了一种由 Mo 单原子 (SAs) 和 MoO ₂纳米颗粒 (NPs) (Mo _SAs -MoO ₂ @NC) 组成的催化剂，这是了解 SAs 如何对纳米催化剂做出贡献的精确模型。实验结果和密度泛函理论计算均表明，氮掺杂碳上的 Mo SAs 为硝基还原提供了反应区，而 MoO ₂是分解水合肼产生 H ^⋆的活性位点。由于 Mo SAs 和 MoO _{2之间的协同作用}NPs，该催化剂表现出类似贵金属的催化活性（4 分钟时 100% 转化率），用于防脱氯转移氢化。此外，在没有氢源的情况下，通过电化学测试验证了催化剂上的氢迁移。该工作为进一步研究单原子在纳米粒子催化剂中的共存提供了模型。