The performances of single-atom catalysts are governed by their local coordination environments. Here, a thermal replacement strategy is developed for the synthesis of single-atom catalysts with precisely controlled and adjustable local coordination environments. A series of Co-S_xN_4−x (x = 0, 1, 2, 3) single-atom catalysts are successfully synthesized by thermally replacing coordinated N with S at elevated temperature, and a volcano relationship between coordinations and catalytic performances toward electrochemical CO₂ reduction is observed. The Co-S₁N₃ catalyst has the balanced COOH*and CO* bindings, and thus locates at the apex of the volcano with the highest performance toward electrochemical CO₂ reduction to CO, with the maximum CO Faradaic efficiency of 98 ± 1.8% and high turnover frequency of 4564 h⁻¹ at an overpotential of 410 mV tested in H-cell with CO₂-saturated 0.5 M KHCO₃, surpassing most of the reported single-atom catalysts. This work provides a rational approach to control the local coordination environment of the single-atom catalysts, which is important for further fine-tuning the catalytic performance.

单原子催化剂的性能取决于其局部配位环境。在这里，开发了一种热替代策略，用于合成具有精确控制和可调节局部配位环境的单原子催化剂。通过在高温下用S热取代配位N，成功合成了一系列Co-S _x N _4−x ( x = 0, 1, 2, 3)单原子催化剂，并发现配位与催化性能之间的火山关系观察到电化学CO ₂还原。 Co-S ₁ N ₃催化剂具有平衡的COOH*和CO*结合，因此位于火山的顶点，具有最高的电化学CO ₂还原成CO的性能，最大CO法拉第效率为98 ± 1.8%在使用CO ₂饱和的0.5 M KHCO ₃的H电池中测试，在410 mV的过电势下，转换频率高达4564 h ^-1 ，超过了大多数报道的单原子催化剂。这项工作为控制单原子催化剂的局部配位环境提供了一种合理的方法，这对于进一步微调催化性能具有重要意义。