Electrocatalytic CO₂ reduction to generate multicarbon products is of interest for applications in artificial photosynthetic schemes. This is a particularly attractive goal for CO₂ reduction by copper electrodes, where a broad range of hydrocarbon products can be generated but where selectivity for C–C coupled products relative to CH₄ and H₂ remains an impediment. Herein we report a simple yet highly selective catalytic system for CO₂ reduction to C_≥2 hydrocarbons on a polycrystalline Cu electrode in bicarbonate aqueous solution that uses N-substituted pyridinium additives. Selectivities of 70–80% for C₂ and C₃ products with a hydrocarbon ratio of C_≥2/CH₄ significantly greater than 100 have been observed with several additives. ¹³C-labeling studies verify CO₂ to be the sole carbon source in the C_≥2 hydrocarbons produced. Upon electroreduction, the N-substituted pyridinium additives lead to film deposition on the Cu electrode, identified in one case as the reductive coupling product of N-arylpyridinium. Product selectivity can also be tuned from C_≥2 species to H₂ (∼90%) while suppressing methane with certain N-heterocyclic additives.

中文翻译：

---

N取代的吡啶鎓添加剂对多晶铜上_C≥2产物的CO ₂还原选择性

电催化还原CO ₂以产生多碳产物对于在人工光合作用方案中的应用是令人感兴趣的。对于铜电极还原CO _2来说，这是一个特别有吸引力的目标，在铜电极上可以生成多种烃类产物，但相对于CH ₄和H ₂而言，CC偶联产物的选择性仍然受到阻碍。本文中，我们报告了一种简单而高度选择性的催化系统，用于在使用N-取代的吡啶鎓添加剂的碳酸氢盐水溶液中的多晶Cu电极上将CO ₂还原为_C≥2碳氢化合物。C ₂和C _3的选择性为70–80％使用几种添加剂已观察到碳氢化合物比率_C≥2 / CH ₄明显大于100的产品。¹³ C标记研究证实，CO ₂是所产生的_C≥2烃中唯一的碳源。在电还原时，N-取代的吡啶鎓添加剂导致在Cu电极上的膜沉积，在一种情况下被确定为N-芳基吡啶鎓的还原偶联产物。产品选择性也可以从_C≥2种调整为H ₂（〜90％），同时用某些N杂环添加剂抑制甲烷。