Electrocatalytic CO₂ reduction reaction (CO₂RR), a potential source of fuels and energy-rich chemical feedstock, is a promising approach to reduce current fossil fuel-based production as well as to reduce anthropogenic carbon emission. Cu-based electrocatalysts have drawn noteworthy attention due to their capability to produce C₁, and C₂₊ products. However, challenges still exist in materials design towards highly active, selective and stable C─C coupling to produce high value-added fuels and chemicals. Meanwhile, CO₂RR is a typical electrochemical reaction that occurs on the gas-liquid-solid three phase contact, therefore mass transportation stands as a key factor that influences both the activity as well as selectivity. Consequently, many efforts have been made towards the development of catalysts, electrolyte and electrochemical cell systems, to optimize the intrinsic activity and selectivity as well as mass transfer behavior. The goal of this review is to provide in-depth understanding on active sites engineering of the Cu based electrocatalysts and mass transfer ability of the cell configuration. In the first part, strategies to regulate the coordination state and electronic structure of Cu atoms were introduced for the optimization of the binding strength of key intermediates such as ∗CO, ∗CHO and ∗OCCO, and for the regulation of intermediates adsorption approach such as the ratio of atop-bound CO to bridge-bound CO, as well as to increase CO∗ coverages and lower the CO∗ dimerization barrier. In the second part, the design of new electrode structures and electrocatalytic cells to tune the mass transfer behavior of CO₂RR reagents to enable unobstructed CO₂ diffusion pathway and altered protons supply for the improvement of the activity at low overpotential and selectivity at high current density have been systematically discussed. Finally, we summarized the design principles for the Cu based electrocatalysts, the electrode structure, and cell configuration to optimize the adsorption/desorption of intermediates and diffusion of reagents and products. However, challenges in optimizing the reaction pathway still exist, we put up with some perspectives for future investigation of CO₂RR mechanism, and promising strategies for stable higher C₂₊ production with high current density.

电催化CO ₂还原反应（CO ₂ RR）是一种燃料和富含能源的化学原料的潜在来源，是减少当前基于化石燃料的生产以及减少人为碳排放的一种有前途的方法。铜基电催化剂由于具有生产C ₁和C ₂₊产物的能力而备受关注。但是，材料设计仍然面临着向高活性，选择性和稳定的CC连接生产高附加值燃料和化学品的挑战。同时，CO ₂RR是在气-液-固三相接触上发生的典型电化学反应，因此，传质是影响活性和选择性的关键因素。因此，为开发催化剂，电解质和电化学电池系统做出了许多努力，以优化内在活性和选择性以及传质行为。这篇综述的目的是提供对基于铜的电催化剂的活性位点工程和电池构型的传质能力的深入了解。在第一部分中，介绍了调节Cu原子的配位态和电子结构的策略，以优化∗ CO，∗ CHO和∗ OCCO等关键中间体的结合强度，用于调节中间体吸附方法，例如顶部结合的CO与桥结合的CO的比例，以及增加CO *的覆盖率和降低CO *的二聚化势垒。在第二部分中，设计新的电极结构和电催化池以调节CO的传质行为已经系统地讨论了_2种RR试剂，这些试剂可实现畅通的CO ₂扩散途径和改变的质子供应，以改善低过电势下的活性和高电流密度下的选择性。最后，我们总结了铜基电催化剂的设计原理，电极结构和电池结构，以优化中间体的吸附/解吸以及试剂和产物的扩散。然而，在优化反应途径方面仍然存在挑战，我们为将来对CO ₂ RR机理的研究提出了一些观点，并提出了在高电流密度下稳定生产更高的C _2+的有前途的策略。