The most difficulty of efficient CO₂ electroreduction lies in the activation step that turns CO₂ into the CO₂⁻ radicals or other intermediates that can be further converted. To overcome this bottleneck, many efforts have been devoted to develop electrocatalysts to lower the overpotential of CO₂ activation, but they inevitably involve complicated or/and unscalable synthesis methods. Here we reported that the SO₄²⁻ ion modified metal foils, including Zn, Ag, Au and Cu, demonstrated ∼6.5, 1.4, 14 and 2.5 times of CO faradaic efficiency in K₂SO₄ electrolyte compared to KHCO₃ electrolyte at −1.05 V vs. RHE. According to both experimental and DFT studies, the electron-rich metal-SO₄ adlayer can activate CO₂ by bending the linear molecule of CO₂ through donating electrons to the antibonding orbital of CO₂, thus facilitating the formation of key intermediate *CO₂⁻. Moreover, the adsorption of H⁺ on metal sites is restrained by the metal-SO₄ adlayer, leading to a suppressed H₂ evolution activity. From a broader perspective, many catalysts can benefit from this approach to achieve more efficient CO₂ electrochemical reduction.

_{有效CO 2}电还原的最大困难在于将CO ₂转化为CO ₂ ^-自由基或其他可以进一步转化的中间体的活化步骤。为了克服这一瓶颈，许多努力致力于开发电催化剂以降低 CO ₂活化的过电势，但它们不可避免地涉及复杂或/和不可扩展的合成方法。在这里，我们报道了 SO ₄ ^{2-离子改性金属箔（包括 Zn、Ag、Au 和 Cu）在 K} ₂ SO ₄电解质中的 CO 法拉第效率是 KHCO ₃的 ~6.5、1.4、14 和 2.5 倍电解质为 -1.05 V vs. RHE。根据实验和DFT研究，富电子金属-SO ₄吸附层可以通过向CO 2 的反键轨道提供电子来弯曲CO ₂的线性分子来激活CO _{2 ，​​从而促进关键中间体* CO 2的}形成^-。^{此外，H +}在金属位点上的吸附受到金属-SO ₄吸附层的限制，导致H ₂释放活性受到抑制。从更广泛的角度来看，许多催化剂可以从这种方法中受益，以实现更高效的 CO ₂电化学还原。