Formate can be synthesized electrochemically by CO₂ reduction reaction (CO₂RR) or formaldehyde oxidation reaction (FOR). The CO₂RR approach suffers from kinetic-sluggish oxygen evolution reaction at the anode. To this end, an electrochemical system combining cathodic CO₂RR with anodic FOR was developed, which enables the formate electrosynthesis at ultra-low voltage. Cathodic CO₂RR employing the BiOCl electrode in H-cell exhibited formate Faradaic efficiency (FE) higher than 90% within a wide potential range from − 0.48 to − 1.32 V_RHE. In flow cell, the current density of 100 mA cm⁻² was achieved at − 0.67 V_RHE. The anodic FOR using the Cu₂O electrode displayed a low onset potential of − 0.13 V_RHE and nearly 100% formate and H₂ selectivity from 0.05 to 0.35 V_RHE. The CO₂RR and FOR were constructed in a flow cell through membrane electrode assembly for the electrosynthesis of formate, where the CO₂RR//FOR delivered an enhanced current density of 100 mA cm⁻² at 0.86 V. This work provides a promising pair-electrosynthesis of value-added chemicals with high FE and low energy consumption.

甲酸盐可以通过CO ₂还原反应(CO ₂ RR)或甲醛氧化反应(FOR)电化学合成。CO ₂ RR 方法在阳极处存在动力学缓慢的氧气析出反应。为此，开发了一种结合阴极 CO ₂ RR 和阳极 FOR 的电化学系统，该系统能够在超低电压下进行甲酸盐电合成。在 H 电池中采用 BiOCl 电极的阴极 CO _{2 RR 在 − 0.48 至 − 1.32} V _RHE的宽电位范围内表现出高于 90% 的甲酸盐法拉第效率 (FE) 。在流通池中，100 mA cm ^-2的电流密度在 - 0.67 V _RHE下实现. 使用 Cu _{2 O 电极的阳极 FOR 显示出 - 0.13} V _RHE的低起始电位和从 0.05 到 0.35 V _RHE的近 100% 的甲酸盐和 H ₂选择性。CO ₂ RR 和 FOR 通过膜电极组件在流通池中构建，用于甲酸盐的电合成，其中 CO _{2 RR//FOR 在 0.86 V 下提供了 100 mA cm} ^-2的增强电流密度。这项工作提供了一个有希望的高FE、低能耗的高附加值化学品的对电合成。