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

Research output: Contribution to journalArticlepeer-review

14 Scopus citations

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 FECO of 75.9% with a total current density of 27.3 mA/cm2 at a cell voltage of 3.1 V. A FECO 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.
Original languageEnglish (US)
Pages (from-to)1890-1895
Number of pages6
JournalScience Bulletin
Volume64
Issue number24
DOIs
StatePublished - Dec 30 2019
Externally publishedYes

ASJC Scopus subject areas

  • General

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