A bio-inspired O2-tolerant catalytic CO2 reduction electrode

Xu Lu; Zhan Jiang; Xiaolei Yuan; Yueshen Wu; Richard Malpass-Evans; Yiren Zhong; Yongye Liang; Neil B McKeown; Hailiang Wang

doi:10.1016/j.scib.2019.04.008

A bio-inspired O₂-tolerant catalytic CO₂ reduction electrode

Sci Bull (Beijing). 2019 Dec 30;64(24):1890-1895. doi: 10.1016/j.scib.2019.04.008. Epub 2019 Apr 4.

Authors

Xu Lu¹, Zhan Jiang², Xiaolei Yuan³, Yueshen Wu¹, Richard Malpass-Evans⁴, Yiren Zhong¹, Yongye Liang⁵, Neil B McKeown⁶, Hailiang Wang⁷

Affiliations

¹ Department of Chemistry, Yale University, New Haven, CT 06520, USA; Energy Sciences Institute, Yale University, West Haven, CT 06516, USA.
² Department of Materials Science and Engineering, Shenzhen Key Laboratory of Printed Organic Electronics, Southern University of Science and Technology, Shenzhen 518055, China.
³ Department of Chemistry, Yale University, New Haven, CT 06520, USA; Energy Sciences Institute, Yale University, West Haven, CT 06516, USA; Institute of Functional Nano and Soft Materials, Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123, China.
⁴ EastChem, School of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, UK.
⁵ Department of Materials Science and Engineering, Shenzhen Key Laboratory of Printed Organic Electronics, Southern University of Science and Technology, Shenzhen 518055, China. Electronic address: liangyy@sustc.edu.cn.
⁶ EastChem, School of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, UK. Electronic address: neil.mckeown@ed.ac.uk.
⁷ Department of Chemistry, Yale University, New Haven, CT 06520, USA; Energy Sciences Institute, Yale University, West Haven, CT 06516, USA. Electronic address: hailiang.wang@yale.edu.

PMID: 36659584
DOI: 10.1016/j.scib.2019.04.008

Abstract

The electrochemical reduction of CO₂ to give CO in the presence of O₂ would allow the direct valorization of flue gases from fossil fuel combustion and of CO₂ captured from air. However, it is a challenging task because O₂ reduction is thermodynamically favored over that of CO₂. 5% O₂ in CO₂ near catalyst surface is sufficient to completely inhibit the CO₂ reduction reaction. Here we report an O₂-tolerant catalytic CO₂ reduction electrode inspired by part of the natural photosynthesis unit. The electrode comprises of heterogenized cobalt phthalocyanine molecules serving as the cathode catalyst with >95% Faradaic efficiency (FE) for CO₂ reduction to CO coated with a polymer of intrinsic microporosity that works as a CO₂-selective layer with a CO₂/O₂ selectivity of ∼20. Integrated into a flow electrolytic cell, the hybrid electrode operating with a CO₂ feed gas containing 5% O₂ exhibits a FE_CO of 75.9% with a total current density of 27.3 mA/cm² at a cell voltage of 3.1 V. A FE_CO of 49.7% can be retained when the O₂ fraction increases to 20%. Stable operation for 18 h is demonstrated. The electrochemical performance and O₂ tolerance can be further enhanced by introducing cyano and nitro substituents to the phthalocyanine ligand.

Keywords: Cooperative catalysis; Electrochemical CO(2) reduction; Gas separation; O(2) tolerance; Polymer of intrinsic microporosity.