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Abstract Electrochemical CO2reduction reaction (CO2‐RR) in non‐aqueous electrolytes offers significant advantages over aqueous systems, as it boosts CO2solubility and limits the formation of HCO3−and CO32−anions. Metal–organic frameworks (MOFs) in non‐aqueous CO2‐RR makes an attractive system for CO2capture and conversion. However, the predominantly organic composition of MOFs limits their electrical conductivity and stability in electrocatalysis, where they suffer from electrolytic decomposition. In this work, electrically conductive and stable Zirconium (Zr)‐based porphyrin MOF, specifically PCN‐222, metalated with a single‐atom Cu has been explored, which serves as an efficient single‐atom catalyst (SAC) for CO2‐RR. PCN‐ 222(Cu) demonstrates a substantial enhancement in redox activity due to the synergistic effect of the Zr matrix and the single‐atom Cu site, facilitating complete reduction of C2species under non‐aqueous electrolytic conditions. The current densities achieved (≈100 mA cm−2) are 4–5 times higher than previously reported values for MOFs, with a faradaic efficiency of up to 40% for acetate production, along with other multivariate C2products, which have never been achieved previously in non‐aqueous systems. Characterization using X‐ray and various spectroscopic techniques, reveals critical insights into the role of the Zr matrix and Cu sites in CO2reduction, benchmarking PCN‐222(Cu) for MOF‐based SAC electrocatalysis.
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Tailoring Electrochemical CO 2 Reduction on Copper by Reactive Ionic Liquid and Native Hydrogen Bond Donors
Abstract Electrochemical CO2reduction (CO2RR) on copper (Cu) shows promise for higher‐value products beyond CO. However, challenges such as the limited CO2solubility, high overpotentials, and the competing hydrogen evolution reaction (HER) in aqueous electrolytes hinder the practical realization. We propose a functionalized ionic liquid (IL) which generates ion‐CO2adducts and a hydrogen bond donor (HBD) upon CO2absorption to modulate CO2RR on Cu in a non‐aqueous electrolyte. As revealed by transient voltammetry, electrochemical impedance spectroscopy (EIS), and in situ surface‐enhanced Raman spectroscopy (SERS) complemented with image charge augmented quantum‐mechanical/molecular mechanics (IC‐QM/MM) computations, a unique microenvironment is constructed. In this microenvironment, the catalytic activity is primarily governed by the IL and HBD concentrations; former controlling the double layer thickness and the latter modulating the local proton availability. This translates to ample CO2availability, reduced overpotential, and suppressed HER where C4products are obtained. This study deepens the understanding of electrolyte effects in CO2RR and the role of IL ions towards electrocatalytic microenvironment design.
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- Award ID(s):
- 2045111
- PAR ID:
- 10518938
- Publisher / Repository:
- Wiley
- Date Published:
- Journal Name:
- Angewandte Chemie International Edition
- Volume:
- 63
- Issue:
- 1
- ISSN:
- 1433-7851
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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