As the world tries to move away from using fossil fuels, the CO₂ reduction reaction (CO₂RR) has become an important method to generate liquid fuels which will likely remain an important component of our energy infrastructure. As a result, every aspect of the process has been, both figuratively and literally, put under the microscope. For example, the composition and pH of electrolytes play a significant role in the electrocatalytic CO₂RR activity and selectivity. Writing in ACS Catalysis a team led by Ming Ma from Xi’an Jiaotong University examined how electrolytes can be altered during electrocatalysis — understanding these changes is crucial for future device design.

In a cell fitted with an AEM and initially using K₂SO₄ as electrolyte, they found that within two hours of electrocatalysis, the majority charge carrier through the AEM from catholyte to anolyte switched from SO₄^2– to HCO₃^– (formed by the reaction of CO₂ with hydroxide generated at the cathode). Switching to a CEM, K⁺ was initially the main charge carrier to the catholyte but was soon replaced by H⁺ (generated by water oxidation at the anode).

随着世界试图摆脱使用化石燃料，CO ₂还原反应 (CO ₂ RR) 已成为生产液体燃料的重要方法，而液体燃料可能仍然是我们能源基础设施的重要组成部分。结果，这个过程的每个方面，无论是象征性的还是字面意义上的，都被置于显微镜下。例如，电解质的组成和pH值对电催化CO ₂ RR活性和选择性起着重要作用。西安交通大学的 Ming Ma 领导的团队在《ACS Catathesis》上撰文，研究了电解质在电催化过程中如何发生变化——了解这些变化对于未来的设备设计至关重要。

在配备 AEM 并最初使用 K ₂ SO ₄作为电解质的电池中，他们发现在电催化的两个小时内，通过 AEM 从阴极电解液到阳极电解液的大多数电荷载流子从 SO ₄ ^2–转变为 HCO ₃ ^– （由CO ₂与阴极产生的氢氧化物的反应）。切换到 CEM 后，K ⁺最初是阴极电解液的主要电荷载体，但很快被 H ⁺ （由阳极水氧化产生）取代。