Atomically dispersed transition metals on carbon-based aromatic substrates are an emerging class of electrocatalysts for the electroreduction of CO₂. However, electron delocalization of the metal site with the carbon support via d-π conjugation strongly hinders CO₂ activation at the active metal centers. Herein, we introduce a strategy to attenuate the d-π conjugation at single Ni atomic sites by functionalizing the support with cyano moieties. In situ attenuated total reflection infrared spectroscopy and theoretical calculations demonstrate that this strategy increases the electron density around the metal centers and facilitates CO₂ activation. As a result, for the electroreduction of CO₂ to CO in aqueous KHCO₃ electrolyte, the cyano-modified catalyst exhibits a turnover frequency of ~22,000 per hour at −1.178 V versus the reversible hydrogen electrode (RHE) and maintains a Faradaic efficiency (FE) above 90% even with a CO₂ concentration of only 30% in an H-type cell. In a flow cell under pure CO₂ at −0.93 V versus RHE the cyano-modified catalyst enables a current density of −300 mA/cm² with a FE above 90%.

碳基芳族基质上原子分散的过渡金属是一类新兴的用于CO ₂电还原的电催化剂。然而，金属位点与碳载体通过d-π共轭的电子离域强烈阻碍了活性金属中心处的CO ₂活化。在此，我们引入了一种通过用氰基部分功能化支撑来减弱单个 Ni 原子位点的 d-π 共轭的策略。原位衰减全反射红外光谱和理论计算表明该策略增加了金属中心周围的电子密度并促进CO ₂活化。因此，对于在水性 KHCO ₃电解质中将 CO _{2 电}还原为 CO，氰基改性催化剂相对于可逆氢电极 (RHE) 在 -1.178 V 下表现出约 22,000 次/小时的转换频率，并保持法拉第效率 (即使 H 型电池中 CO ₂浓度仅为 30%，FE）也高于 90%。在纯 CO ₂条件下、相对于 RHE 为 -0.93 V 的流通池中，氰基改性催化剂可实现 -300 mA/cm ²的电流密度，且 FE 高于 90%。