Single-atom catalysts have great potential in electrochemical CO₂ reduction reaction (CO₂RR); however, plenty of single-atom sites are embedded inside without catalytic performance and most catalysts are powder-based with binding procedure, causing a relatively low current density. Herein, a strategy is proposed to maximize the utilization of single-atom cobalt sites via constructing a free-standing, cross-linked and high-yield carbon membrane (denoted as CoSA/HCNFs). The 3D net-like CoSA/HCNFs nanofibers with continuous porous structure can facilitate large electrochemical active surface areas and be in favor of the reactant transportation, which generate abundant effective cobalt single atoms for CO₂ reduction. The highly utilization of single-atom Co sites eventually lead to CO with 91% Faradaic efficiency and 67 mA cm⁻² current density in a typical H-type cell, 92% Faradaic efficiency as well as 211 mA cm⁻² current density in a flow cell, respectively. This strategy for large-scale production of single-atom membranes could also be easily expanded to extensive electrolysis and energy storage devices.

单原子催化剂在电化学CO ₂还原反应（CO ₂ RR）中具有巨大的潜力。但是，许多单原子位点埋在内部却没有催化性能，并且大多数催化剂都是基于粉末的结合程序，从而导致相对较低的电流密度。本文中，提出了一种通过构建独立的，交联的且高产率的碳膜（表示为CoSA / HCNFs）来最大程度地利用单原子钴位点的策略。具有连续多孔结构的3D网状CoSA / HCNFs纳米纤维可以促进大的电化学活性表面积并有利于反应物的运输，从而为CO ₂生成大量有效的钴单原子减少。单原子Co位置的高利用率最终导致典型的H型电池的CO具有91％的法拉第效率和67 mA cm ^-2的电流密度，92％的Faradaic效率以及211 mA cm ^-2的电流密度。流通池。大规模生产单原子膜的策略也可以轻松扩展到广泛的电解和能量存储设备。