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The insensitive cation effect on a single atom Ni catalyst allows selective electrochemical conversion of captured CO2 in universal media
Energy & Environmental Science ( IF 32.5 ) Pub Date : 2022-08-22 , DOI: 10.1039/d2ee01825j
Jae Hyung Kim , Hyunsung Jang , Gwangsu Bak , Woong Choi , Hyewon Yun , Eun Chong Lee , Dongjin Kim , Jiwon Kim , Si Young Lee , Yun Jeong Hwang

The direct electroconversion of captured CO2 is attracting attention as a streamlined manner for carbon capture and utilization, omitting energy-demanding CO2 separation processes. In amine-based conventional capturing media, however, the reaction inevitably takes place in the presence of bulky ammonium cations, leading to low charge density on the electrode surface and consequent inferior reactivity. Hence, discovering cation-insensitive electrode materials is of prime importance to electrochemically activate the captured CO2, but has not yet been explored. Here, we report that a single atom Ni catalyst embedded on N-doped carbon (Ni–N/C) exhibits weak cation sensitivity, which allows a notably high CO selectivity (64.9%) at −50 mA cm−2 integrated with a membrane electrode assembly in a CO2-capturing monoethanolamine-based electrolyte. Moreover, the weak cation sensitivity of Ni–N/C enables it to exhibit universally high CO selectivity even in a bulkier electrolyte, whereas the Ag catalyst shows a decrease depending on the type of amine. We propose that the positively shifted potential of the zero charge of Ni–N/C enables the high surface charge density to be maintained even in the presence of bulky cations, allowing high CO production activity in various capturing solutions. These trends provide insights into selective catalyst design for the electroconversion of captured CO2 in universal media.

中文翻译:

对单原子 Ni 催化剂的不敏感阳离子效应允许在通用介质中选择性电化学转化捕获的 CO2

捕获的CO 2的直接电转化作为一种​​碳捕获和利用的流线型方式引起了人们的关注,它省略了对能量要求高的CO 2分离过程。然而,在基于胺的常规捕获介质中,反应不可避免地发生在大体积铵阳离子的存在下,导致电极表面的电荷密度低,从而导致反应性差。因此,发现对阳离子不敏感的电极材料对于电化学活化捕获的CO 2至关重要,但尚未进行探索。在这里,我们报告了嵌入 N 掺杂碳 (Ni-N/C) 上的单原子 Ni 催化剂表现出较弱的阳离子敏感性,这在 -50 mA cm -2时允许显着高的 CO 选择性 (64.9%)与膜电极组件集成在捕获CO 2的单乙醇胺基电解质中。此外,Ni-N/C 的弱阳离子敏感性使其即使在体积较大的电解质中也能表现出普遍高的 CO 选择性,而 Ag 催化剂的降低取决于胺的类型。我们提出,Ni-N/C 零电荷的正移电位即使在存在大体积阳离子的情况下也能保持高表面电荷密度,从而在各种捕获溶液中实现高 CO 产生活性。这些趋势为通用介质中捕获的 CO 2电转化的选择性催化剂设计提供了见解。
更新日期:2022-08-22
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