Copper (Cu)-based materials are known as the most attractive catalysts for electrochemical carbon dioxide reduction reaction (CO₂RR), especially the Cu⁺ species (e.g., Cu₂O), which show excellent capability for catalyzing CO₂ to C₂₊ chemicals because of their unique electronic structure. However, the active Cu⁺ species are prone to be reduced to metallic Cu under an electroreduction environment, thus resulting in fast deactivation and poor selectivity. Here, we developed an advanced surface modification strategy to maintain the active Cu⁺ species via assembling a protective layer of metal–organic framework (copper benzenetricarboxylate, CuBTC) on the surface of Cu₂O octahedron (Cu₂O@CuBTC). It's encouraging to see that the Cu₂O@CuBTC heterostructure outperforms the bare Cu₂O octahedron in catalyzing CO₂ to C₂₊ chemicals and dramatically enhances the ratio of C₂H₄/CH₄ products. A systematic study reveals that the introduced CuBTC shell plays a critical role in maintaining the active Cu⁺ species in Cu₂O@CuBTC heterostructure under reductive conditions. This work offers a practical strategy for improving the catalytic performance of CO₂RR over copper oxides and also establishes a route to maintain the state of valence-sensitive catalysts.

铜(Cu)基材料被认为是电化学二氧化碳还原反应(CO ₂ RR)中最有吸引力的催化剂，尤其是Cu ⁺物质(例如Cu ₂ O)，其表现出优异的催化CO ₂到C _2的能力+化学品因其独特的电子结构。然而，活性Cu ⁺物种在电还原环境下容易被还原为金属Cu，导致失活速度快且选择性差。在这里，我们开发了一种先进的表面改性策略来保持活性 Cu ⁺_{通过在Cu 2} O八面体(Cu ₂ O@ CuBTC)表面组装金属有机骨架保护层(苯三甲酸铜，CuBTC)来形成物种。令人鼓舞的是，Cu _{2 O@CuBTC异质结构在催化CO 2}生成C ₂₊化学品方面优于裸露的Cu ₂ O八面体，并显着提高了C ₂ H ₄ /CH ₄产物的比率。系统研究表明，引入的CuBTC壳对于维持Cu ₂中的活性Cu ^{+物种起着关键作用}还原条件下的O@CuBTC异质结构。_{这项工作为提高CO 2} RR相对于铜氧化物的催化性能提供了实用策略，并建立了维持价态敏感催化剂状态的途径。