Electrocatalytic Reduction of Low Concentrations of CO2 Gas in a Membrane Electrode Assembly Electrolyzer,ACS Energy Letters

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Electrocatalytic Reduction of Low Concentrations of CO2 Gas in a Membrane Electrode Assembly Electrolyzer
ACS Energy Letters ( IF 19.3 ) Pub Date : 2021-09-10 , DOI: 10.1021/acsenergylett.1c01797
Dongjin Kim _{1,

2} , Woong Choi ₁ , Hee Won Lee _{1,

3} , Si Young Lee _{4,

5} , Yongjun Choi _{1,

3} , Dong Ki Lee _{1,

3,

6} , Woong Kim ₂ , Jonggeol Na ₇ , Ung Lee _{1,

3,

6} , Yun Jeong Hwang _{4,

5} , Da Hye Won _{1,

3}

Affiliation

The direct conversion of low concentrations of CO₂ is an essential approach, considering the expensive gas conditioning process for pure CO₂, but has not yet been intensely studied in a membrane electrode assembly (MEA) electrolyzer. Herein, we explored the CO₂ reduction with various CO₂ concentrations in a zero-gap MEA electrolyzer and found that suppressing the hydrogen evolution reaction (HER) became more critical at low concentrations of CO₂. We demonstrate that a Ni single-atom (Ni-N/C) catalyst exhibits a high tolerance toward low CO₂ partial pressure (P_CO2) because of the intrinsically large activation energy of the HER. Ni-N/C outperformed the CO productivity of Ag nanoparticles, especially at low concentrations of CO₂ in the zero-gap MEA. When the P_CO2 was lowered from 1.0 to 0.1 atm, Ni-N/C maintained >93% of CO Faradaic efficiency (FE_CO), but Ag nanoparticles showed a decrease in FE_CO from 94% to 40%. Furthermore, on the basis of a computational fluid dynamics simulation, we developed extrinsic operating conditions controlling the water transfer from the anolyte to the catalyst layer and improved CO selectivity at low CO₂ concentrations in the MEA electrolyzer.

中文翻译：

膜电极组装电解槽中低浓度 CO2 气体的电催化还原

考虑到纯 CO ₂的昂贵气体调节过程，低浓度 CO ₂的直接转化是一种必不可少的方法，但尚未在膜电极组件 (MEA) 电解槽中进行深入研究。在此，我们探索了在零间隙 MEA 电解槽中使用不同 CO ₂浓度进行的 CO ₂还原，发现在低浓度 CO _{2 下}抑制析氢反应 (HER) 变得更加关键。我们证明了 Ni 单原子 (Ni-N/C) 催化剂对低 CO ₂分压 ( P _CO2) 因为 HER 固有的大活化能。Ni-N/C 优于 Ag 纳米粒子的 CO 生产率，尤其是在零间隙 MEA 中的低 CO ₂浓度下。当P _CO2从 1.0 降低到 0.1 atm 时，Ni-N/C 保持了大于 93% 的 CO 法拉第效率 (FE _CO )，但 Ag 纳米颗粒显示出 FE _CO从 94%降低到 40%。此外，在计算流体动力学模拟的基础上，我们开发了控制水从阳极电解液转移到催化剂层的外在操作条件，并提高了 MEA 电解槽中低 CO ₂浓度下的CO 选择性。

更新日期：2021-10-08

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