Hierarchical Copper with Inherent Hydrophobicity Mitigates Electrode Flooding for High-Rate CO₂ Electroreduction to Multicarbon Products

Abstract

Copper is currently the material with the most promise as catalyst to drive carbon dioxide (CO 2 ) electroreduction to produce value-added multicarbon (C 2+ ) compounds. However, a copper catalyst on a carbon-based gas diffusion layer electrode often has poor stabilityespecially when performing at high current densitiesowing to electrolyte flooding caused by the hydrophobicity decrease of the gas diffusion layer during operation. Here, we report a bioinspired copper catalyst on a gas diffusion layer that mimics the unique hierarchical structuring of Setaria's hydrophobic leaves. This hierarchical copper structure endows the CO 2 reduction electrode with sufficient hydrophobicity to build a robust gas−liquid−solid triple-phase boundary, which can not only trap more CO 2 close to the active copper surface but also effectively resist electrolyte flooding even under high-rate operation. We consequently achieved a high C 2+ production rate of 255 ± 5.7 mA cm −2 with a 64 ± 1.4% faradaic efficiency, as well as outstanding operational stability at 300 mA cm −2 over 45 h in a flow reactor, largely outperforming its wettable copper counterparts.

Boosting CO2 electroreduction towards C2+ products via CO* intermediate manipulation on copper-based catalysts

“…For example, the synergistic effect of metal doping and oxygen defects on the surface of Cu could enhance the CO 2 RR to yield C 2 H 4 significantly 261 via the field-induced enhancement effect of Cu nanoneedles combined with a stable three-phase interface created by a hierarchical copper structure on a gas diffusion electrode, where the electrocatalysis of CO 2 to C 2+ products with an industry-scale current density and selectivity was acheived. 170…”

Highly Efficient Electrocatalytic CO2 Reduction to C2+ Products on a Poly(ionic liquid)‐Based Cu0–CuI Tandem Catalyst

“…[25] We also observed the Raman peak at � 2100 cm À 1 corresponding to the stretching vibration mode of *CO with "end-on" configuration (Figure 5c). [24,25] It quickly disappears at the cathodic potential more negative than À 0.20 V, suggesting fast reduction kinetics of *CO. It is worthy to note that a rapid re-oxidization of the Cu surface occurs after the cathodic potential was removed (Figure S36), agreeing well with Gao's study [24a] and our previous results.…”

Customizing the microenvironment of CO2 electrocatalysis via three‐phase interface engineering

“…It usually leads to the destruction of the gas diffusion layer during the reaction. One promising approach to resolve this issue is to use a hydrophobic Cu electrode to mitigate the electrode flooding for CRR, which can ensure the flow cell stable working for 45 h at the 300 mA/cm 2 105 . More studies should be pursued to improve the stability of the electrode in the flow cell. Organic molecules and polymers can offer a certain freedom degree to adjust the local environment of the electrodes.…”

“…One promising approach to resolve this issue is to use a hydrophobic Cu electrode to mitigate the electrode flooding for CRR, which can ensure the flow cell stable working for 45 h at the 300 mA/cm 2 . 105 More studies should be pursued to improve the stability of the electrode in the flow cell. (2) Organic molecules and polymers can offer a certain freedom degree to adjust the local environment of the electrodes.…”