Electroreduction of CO₂ on Single‐Site Copper‐Nitrogen‐Doped Carbon Material: Selective Formation of Ethanol and Reversible Restructuration of the Metal Sites

Abstract

It is generally believed that CO2 electroreduction to multicarbon products such as ethanol or ethylene may be catalyzed with significant yield only on metallic copper surfaces, implying large ensembles of copper atoms. Here, we report on an inexpensive Cu-N-C material prepared via a simple pyrolytic route that exclusively feature single copper atoms with a CuN4 coordination environment, atomically dispersed in a nitrogen-doped conductive carbon matrix. This material achieves aqueous CO2 electroreduction to ethanol at a Faradaic yield of 55% under optimized conditions (electrolyte: 0.1 M CsHCO3 , potential:-1.2V vs. RHE and gas-phase recycling set up), as well as CO electroreduction to C2-products (ethanol and ethylene) with a Faradaic yield of 80%. During electrolysis the isolated sites transiently convert into metallic copper nanoparticles, as shown by operando XAS analysis, which are likely to be the catalytically active species. Remarkably, this process is reversible and the initial material is recovered intact after electrolysis.

Engineering Local Coordination Environments of Atomically Dispersed and Heteroatom‐Coordinated Single Metal Site Electrocatalysts for Clean Energy‐Conversion

“…Jiao et al demonstrated the formation of C 2 products (e.g., alcohol, ethylene, and ethane) based on atomically dispersed Cu sites on g‐C 3 N 4 , although the FE is low. Recently, Karapinar et al reported the CO 2 electroreduction on CuN 4 sites to produce ethanol at a FE of 55% in 0.1 m CsHCO 3 electrolyte. However, the operando XAS characterization observed the conversion of CuN 4 sites to metallic Cu nanoparticles during the CO 2 RR, which are considered the real active sites.…”

Single‐Atom Iron‐Nitrogen Catalytic Site with Graphitic Nitrogen for Efficient Electroreduction of CO2

“…To date, various electrocatalysts, including heteroatom doped carbon materials„ metal materials, transition metal complexes, single‐atomic catalysts, have been explored for electroreduction CO 2 . Among them, single‐atomic catalysts (SACs) possessed the unique size quantum effect and maximum atomic utilization, which have been demonstrated to be promising materials in electrochemical conversion .…”

Enhanced multi-carbon alcohol electroproduction from CO via modulated hydrogen adsorption

“…he need to utilize carbon and to store intermittent renewable electricity has motivated electrochemical CO 2 reduction (CO 2 R) to carbon-based fuels and chemicals [1][2][3] . Of particular interest is the electroproduction of multi-carbon products (C 2+ ), including gaseous ethylene [4][5][6][7] and liquid oxygenates 3,[8][9][10] such as acetate, ethanol and propanol.…”