Single-atom metal catalysts (SAMCs) have high catalytic activity, but mass production of SAMCs with high metal loading remains challenging. In this work, a two-step and one-pot strategy is presented to prepare mesoporous carbon nitride (CN)-based Cu single-atom catalysts (Cu–CN-x, where x refers to the metal loading in wt %) with ultrahigh metal loadings (e.g., up to 26.6 wt %), in which the mixture of urea and copper chloride is first heated at 180 °C and then calcined at 550 °C. Extended X-ray absorption fine structure analysis demonstrates that a Cu single atom is doped into the skeleton of CN via replacing one carbon atom and bonding with three nitrogen atoms. The resultant Cu–CN-x catalyst displays excellent performance and high stability for catalyzing the reaction of terminal alkynes with atmospheric carbon dioxide, much better than the best reported catalyst, synergistically attributed to both the isolated Cu single atom and porous structure of the support. Density functional theory calculation shows that the reaction between CO₂ and deprotonated phenylacetylene is energetically exothermic on Cu–CN with a reaction energy of about −0.27 eV and an energy barrier of +0.85 eV. This synthetic strategy paves a universal way for mass production of SAMCs with high-density metal loadings.

中文翻译：

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氮化碳基单原子铜催化剂用于大气CO ₂高效炔烃的羧化反应

单原子金属催化剂（SAMC）具有很高的催化活性，但是大规模生产具有高金属负载量的SAMC仍然具有挑战性。在这项工作中，提出了一种分两步一锅的策略来制备超高介孔氮化碳（CN）基Cu单原子催化剂（Cu–CN- x，其中x表示以重量％计的金属负载量）金属负载（例如，高达26.6 wt％），其中尿素和氯化铜的混合物首先在180°C加热，然后在550°C煅烧。扩展的X射线吸收精细结构分析表明，通过取代一个碳原子并与三个氮原子键合，Cu单原子被掺杂到CN的骨架中。生成的Cu–CN- x该催化剂在催化末端炔烃与大气二氧化碳的反应方面显示出优异的性能和高稳定性，远比报道的最佳催化剂好得多，这归因于分离的铜单原子和载体的多孔结构。密度泛函理论计算表明，CO ₂和去质子化的苯乙炔之间的反应在Cu-CN上发生放热反应，反应能约为-0.27 eV，能垒为+0.85 eV。这种合成策略为大规模生产具有高密度金属负载的SAMC铺平了道路。