The control of single metal atomic sites has been extensively studied in the field of single atom catalysts. By contrast, the precise control of the mesoporous structure in the matrix material, which directly correlates with mass diffusions and may play a dominant role in delivering industrially relevant reaction rates, has been overlooked. Here we report a general method for the synthesis of a single atom catalyst with control of the atomic structure of the single atomic site as well as the mesoporous structure of the carbon support for optimized catalytic performance. Various combinations of metal centres (Ni, Co, Mn, Zn, Cu, Sc and Fe) and mass diffusion channels in two dimensions and three dimensions were achieved. Using CO₂ reduction to CO as an example, our Ni single atom catalyst with three-dimensional diffusion channels delivered a practical current of 350 mA cm⁻² while maintaining a 93% CO Faradaic efficiency, representing a sixfold improvement in turnover frequency compared to two-dimensional counterparts.

单金属原子位点的控制在单原子催化剂领域得到了广泛的研究。相比之下，对基质材料中介孔结构的精确控制，它与质量扩散直接相关，并可能在提供工业相关反应速率方面发挥主导作用，却被忽视了。在这里，我们报告了一种合成单原子催化剂的通用方法，该方法通过控制单原子位点的原子结构以及碳载体的介孔结构来优化催化性能。实现了金属中心（Ni、Co、Mn、Zn、Cu、Sc 和 Fe）和二维和三维质量扩散通道的各种组合。使用 CO ₂以还原为 CO 为例，我们的具有三维扩散通道的 Ni 单原子催化剂可提供 350 mA cm ^-2的实际电流，同时保持 93% 的 CO 法拉第效率，与二维对应物相比，转换频率提高了六倍.