The electrocatalytic reduction of CO₂ to produce sustainable fuels and chemicals is attracting great attention. Cu-based catalysts can lead to the production of a range of different molecules, and interestingly the product selectivity strongly depends on the preparation history, although it is not fully understood yet why. We report a novel strategy that allowed us to prepare Cu nanoparticle on carbon catalysts with similar morphologies, but prepared by in-situ reduction of either supported CuS, Cu₂S or CuO nanoparticles. For the first time the evolution of the Cu species was followed under CO₂ and H⁺ reduction conditions using in-situ X-ray absorption spectroscopy. Excellent electrochemical contact between the Cu-based nanoparticles, the carbon support and the carbon-paper substrate was observed, resulting in metallic Cu as the predominant phase under typical electrochemical CO₂ reduction conditions. Even covering less than 4% of the H₂ producing carbon support with Cu-sulfide derived nanoparticles allowed to steer the selectivity to a maximum of 12% Faradaic efficiency for the production of formate. Clear differences between the catalysts derived from CuS, Cu₂S or CuO nanoparticles were observed, which was ascribed to the presence of residual sulfur in the catalysts.

用于生产可持续燃料和化学品的 CO ₂电催化还原引起了极大的关注。铜基催化剂可以产生一系列不同的分子，有趣的是，产物选择性在很大程度上取决于制备历史，尽管尚不完全了解原因。我们报告了一种新策略，该策略允许我们在具有相似形态的碳催化剂上制备 Cu 纳米颗粒，但通过原位还原负载的 CuS、Cu ₂ S 或 CuO 纳米颗粒来制备。首次在 CO ₂和 H ⁺下跟踪了 Cu 物种的演变使用原位 X 射线吸收光谱的还原条件。观察到Cu基纳米颗粒、碳载体和碳纸基材之间的优异电化学接触，导致在典型的电化学CO ₂还原条件下金属Cu作为主要相。即使用硫化铜衍生的纳米粒子覆盖不到 4% 的产生 H _{2 的}碳载体，也允许将选择性控制到最大 12% 的法拉第效率以生产甲酸盐。观察到衍生自 CuS、Cu ₂ S 或 CuO 纳米颗粒的催化剂之间存在明显差异，这归因于催化剂中残留硫的存在。