The electrochemical reduction of CO₂ could play an important role in addressing climate-change issues and global energy demands as part of a carbon-neutral energy cycle. Single-atom catalysts can display outstanding electrocatalytic performance; however, given their single-site nature they are usually only amenable to reactions that involve single molecules. For processes that involve multiple molecules, improved catalytic properties could be achieved through the development of atomically dispersed catalysts with higher complexities. Here we report a catalyst that features two adjacent copper atoms, which we call an ‘atom-pair catalyst’, that work together to carry out the critical bimolecular step in CO₂ reduction. The atom-pair catalyst features stable Cu₁⁰–Cu₁^x+ pair structures, with Cu₁^x+ adsorbing H₂O and the neighbouring Cu₁⁰ adsorbing CO₂, which thereby promotes CO₂ activation. This results in a Faradaic efficiency for CO generation above 92%, with the competing hydrogen evolution reaction almost completely suppressed. Experimental characterization and density functional theory revealed that the adsorption configuration reduces the activation energy, which generates high selectivity, activity and stability under relatively low potentials.

作为碳中性能源循环的一部分，CO ₂的电化学还原可在解决气候变化问题和全球能源需求方面发挥重要作用。单原子催化剂可以显示出出色的电催化性能；但是，鉴于它们的单点性质，它们通常仅适合涉及单个分子的反应。对于涉及多个分子的方法，可以通过开发具有更高复杂性的原子分散催化剂来提高催化性能。在这里，我们报告了一种催化剂，该催化剂具有两个相邻的铜原子，我们称之为“原子对催化剂”，它们共同作用以完成关键的CO ₂还原双分子步骤。原子对催化剂具有稳定的Cu ₁ ⁰-Cu ₁ ^{x +}对结构，Cu ₁ ^{x +}吸附H ₂ O，相邻的Cu ₁ ⁰吸附CO ₂，从而促进CO ₂活化。这样就产生了超过92％的CO生成法拉第效率，同时竞争性的析氢反应几乎被完全抑制了。实验表征和密度泛函理论表明，吸附构型降低了活化能，从而在较低电势下产生了较高的选择性，活性和稳定性。