Electroreduction of CO₂ to target products with high activity and selectivity has techno-economic importance for renewable energy storage and CO₂ utilization. Herein, we report a hierarchical CuS hollow polyhedron (CuS-HP) for electrocatalytic CO₂ reduction (E-CO₂R) in neutral pH aqueous media. Under E-CO₂R conditions, CuS-HP undergoes structural reconstruction into sulfur-doped metallic Cu catalyst, which promotes formate production with Faradaic efficiency >90% in a wide potential range. The durability of the in situ evolved catalyst has been demonstrated by stable operation for 36 h at a formate partial current density of ∼16 mA cm⁻² at −0.6 V versus reversible hydrogen electrode. Theoretical thermodynamic analysis reveals that the sulfur-doped Cu(111) facet is responsible for high formate selectivity by promoting formate production and suppressing hydrogen evolution.

将CO ₂电还原为具有高活性和选择性的目标产品对于可再生能源存储和CO ₂利用具有技术经济意义。本文中，我们报告了在中性pH水溶液中用于电催化还原CO ₂（E-CO ₂ R）的CuS空心多面体（CuS-HP）。在E-CO ₂ R条件下，CuS-HP进行结构重建，成为掺杂硫的金属Cu催化剂，从而在较宽的电位范围内促进了法拉第效率> 90％的甲酸生产。原位生成的催化剂的耐久性已通过在甲酸盐分流密度约为16 mA cm ^-2的条件下稳定运行36小时得到了证明在-0.6 V时相对于可逆氢电极。理论热力学分析表明，掺杂硫的Cu（111）刻面通过促进甲酸盐的产生和抑制氢的释放而对甲酸盐的高选择性起作用。