Atomically dispersed nanocluster catalysts with fully available metal active sites can maximize atom utilization efficiency and deliver unique catalytic performance relative to nanoparticle and single-atom counterparts. Herein, we report a host-guest strategy by synergizing metal-support interaction and spatial confinement effect to access fully exposed cobalt nanoclusters over nitrogen-doped carbon as a highly active, selective, and reusable catalyst (Co loading of 1.6 wt%) for semi-hydrogenation of phenylacetylene. Aberration-corrected high-angle annular dark-field scanning transmission electron microscopy, X-ray photoelectron spectroscopy, and CO-absorbed diffuse reflectance infrared Fourier transform spectroscopy collectively confirm the cobalt nanoclusters were loosely bonded and randomly dispersed over the nitrogen-doped carbon support. This catalyst, with a full metal availability to the reactants, shows an exceptional catalytic activity (turnover frequency of 3132 h^-1) and selectivity (92%) in the semi-hydrogenation of phenylacetylene (1 atm H₂@60 °C), superior to most of the previously reported catalysts. In addition, this catalyst exhibits a wide substrate scope and broad functional-group tolerance. This work may provide an avenue for the design and facile synthesis of fully exposed metal catalysts with high activity.

具有完全可用的金属活性位点的原子分散纳米团簇催化剂可以最大限度地提高原子利用效率，并提供相对于纳米颗粒和单原子对应物的独特催化性能。在此，我们报告了一种主客体策略，通过协同金属-载体相互作用和空间限制效应来获得完全暴露在氮掺杂碳上的钴纳米团簇，作为一种高活性、选择性和可重复使用的催化剂（Co 负载量为 1.6 wt%），用于半-苯乙炔的加氢。像差校正的高角度环形暗场扫描透射电子显微镜、X 射线光电子能谱和 CO 吸收漫反射红外傅立叶变换光谱共同证实钴纳米团簇松散结合并随机分散在氮掺杂的碳载体上。^-1 ) 和苯乙炔半加氢 (1 atm H ₂ @60 °C) 的选择性 (92%) ，优于大多数先前报道的催化剂。此外，该催化剂表现出广泛的底物范围和广泛的官能团耐受性。这项工作可能为设计和轻松合成具有高活性的完全暴露的金属催化剂提供一条途径。