电催化CO2还原的稳定性问题:评论性综述

A critical review of operating stability issues in electrochemical CO2 reduction

端木静雯 ¹高飞跃 ¹高敏锐¹

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作者信息

1. Division of Nanomaterials & Chemistry,Hefei National Laboratory for Physical Sciences at the Microscale,Department of Chemistry,University of Science and Technology of China,Hefei 230026,China
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摘要

电催化二氧化碳还原反应(CO2RR)能够利用可再生电能将CO2转化为高附加值化学品和燃料,是一项有望缓解当下环境挑战的技术方案.本文总结了CO2RR稳定性下降的根本原因,并探讨了解决这一问题的有效策略以及最新的研究进展.首先,在外加电位的作用下,催化剂会发生结构转变,且碳沉积或气体杂质引起的催化剂中毒都会降低CO2RR的稳定性.其次,气体扩散层(GDL)附近发生水淹和盐沉淀会阻碍反应物/生成物的传输,三相界面会受到破坏.在长时间服役时,液压和电流的作用会导致GDL开裂.在电解质方面,碱性电解质会与CO2中和,形成碳酸盐沉淀;而酸性介质腐蚀催化剂,并伴随严重的析氢副反应.另外,电解质中的金属离子杂质的优先还原进一步加剧了稳定性的衰减.深入理解CO2RR中各类失活现象对设计稳定、高效的CO2电催化系统具有指导意义.针对CO2RR稳定性研究目前所面临的困境,本文最后展望了该领域未来的研究方向.

Abstract

Electrocatalytic carbon dioxide reduction reac-tion(CO2RR)offers a promising solution for mitigating en-vironmental challenges by converting CO2 into value-added chemicals and fuels.However,the long-term stability of CO2RR systems remains a major bottleneck impeding large-scale commercial implementation.This review summarizes recent progress on elucidating the root causes underlying stability declines in CO2RR and strategies to address them.First,catalysts undergo structural transformations(e.g.,re-construction,aggregation,dissolution)under applied reduc-tion potentials,decreasing the density of active sites.Catalyst poisoning via carbon deposition or feed impurities(e.g.,SO2)also reduces site availability.Second,gas diffusion layer(GDL)flooding and salt precipitation hinder reactant/product transport and destroy catalyst-electrolyte-gas three-phase in-terfaces.High applied pressures induce GDL cracking over prolonged operation.Third,alkaline electrolytes neutralize with CO2 and precipitate carbonate salts,while acidic media corrode catalysts and favor competing hydrogen evolution reaction.Metal ion impurities deposit on catalyst surfaces further exacerbating decays.Rational catalyst and GDL design can construct stabilized microenvironments,though addi-tional advances in materials properties,operating conditions,and impurity removal are essential to extend CO2RR lifetime for commercial needs(＞50,000 h).Understanding cross-cou-pling between the diverse deteriorative phenomena will ad-vance the development of this important frontier.

关键词

CO2 reduction/stability/catalyst/gas diffusion layer/electrolyte

Key words

CO2 reduction/stability/catalyst/gas diffusion layer/electrolyte

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基金项目

National Basic Research Program of China(2018YFA0702001)

National Natural Science Foundation of China(22225901)

National Natural Science Foundation of China(21975237)

National Natural Science Foundation of China(51702312)

Fundamental Research Funds for the Central Universities(WK2340000101)

University of Science and Technology of China Research Funds of the Double First-Class Initiative(YD2340002007)

University of Science and Technology of China Research Funds of the Double First-Class Initiative(YD9990002017)

Open Funds of the State Key Laboratory of Rare Earth Resource Utilization(RERU2022007)

China Postdoctoral Science Foundation(2023M733371)

China Postdoctoral Science Foundation(2022M723032)

China Postdoctoral Science Foundation(2023T160617)

Natural Science Foundation Youth Project of Anhui Province(2308085QB37)

China National Postdoctoral Program for Innovative Talents(BX2023341)

出版年

2024

中国科学:材料科学(英文)

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