Synthesis of high-loading single-atom catalysts (SACs) with unique coordination structures, especially those p-block main group metals (e.g., In, Sn), to realize electrocatalytic CO₂ reduction reaction (CO₂RR) with high performance remains a challenge. Here, we report a complex-confinement strategy to prepare In–O₂N₂ and In–O₄ SACs on hollow mesoporous nitrogen-doped carbon, with a loading amount as high as 13.02 wt% and 9.89 wt%, respectively. In–O₂N₂ SACs outperform In–O₄ SACs in CO₂RR toward formate production, reaching a high selectivity (95.5%) and partial current density of formate (−58.2 mA cm⁻²). In situ Raman spectroscopy shows that In–O₂N₂ SACs have a sole ∗OCHO intermediate for formate product, whereas both ∗OCHO and ∗COOH intermediates are observed in In–O₄ SACs. Computational calculations elucidate that coordination environment matters greatly in the electronic structure manipulation of In SACs, where a closer position of p-band center to the Fermi level enables In–O₂N₂ SACs to bind and activate CO₂ molecules more favorably.

合成具有独特配位结构的高负载单原子催化剂（SAC），特别是p区主族金属（例如In、Sn），以实现高性能的电催化CO ₂还原反应（CO ₂ RR）仍然是一个研究课题。挑战。在这里，我们报告了一种复杂限制策略，在中空介孔氮掺杂碳上制备In-O ₂ N ₂和In-O ₄ SAC，负载量分别高达13.02 wt%和9.89 wt%。在CO _{2 RR中，} In-O ₂ N ₂ SAC在甲酸盐生产方面优于In-O ₄ SAC ，达到了高甲酸盐选择性（95.5%）和部分电流密度（−58.2 mA cm ^-2）。原位拉曼光谱表明，In–O ₂ N _{2 SAC 具有唯一的*OCHO 中间体作为甲酸盐产物，而在In–O 4} SAC中观察到*OCHO 和*COOH 中间体。计算结果表明，配位环境在In SACs的电子结构操纵中非常重要，其中p带中心距离费米能级更近的位置使得In-O ₂ N ₂ SACs能够更有利地结合和激活CO ₂分子。