Highly Selective Two‐Electron Electrocatalytic CO₂ Reduction on Single‐Atom Cu Catalysts

Abstract

Cu‐based electrocatalysts with high catalytic selectivity for the CO2 reduction reaction present a significant technological challenge. Herein, a catalyst comprised of Cu single atoms in a nitrogen‐doped graphene matrix (Cu–N4–NG) is developed for highly selective electrocatalytic reduction of CO2 to CO. The single‐atom structure and coordination environment of Cu–N4–NG are identified by synchrotron‐based characterization. Compared to a conventional bulk Cu catalyst, Cu–N4–NG achieves a Faradaic efficiency of 80.6% toward CO under a moderate applied potential of −1.0 V versus reversible hydrogen electrode (RHE). Kinetic experiments show that 1) the Cu–N4 moiety favors the CO2 activation step and 2) the moiety‐anchoring graphene facilitates water dissociation, which supplies protons for CO2 reduction. Moreover, density functional theory (DFT) calculations reveal that CO2 reduction is less hindered thermodynamically on Cu–N4–NG compared to the competing hydrogen evolution reaction (HER) due to their limiting potential differences. Therefore, the highest CO selectivity is observed on Cu–N4–NG over the bulk Cu catalyst due to more favorable kinetics and thermodynamics.

Recent advances in single atom catalysts for the electrochemical carbon dioxide reduction reaction

“…[131][132][133][134][135] Additionally, more advanced characterization techniques are needed to be developed to better study the structure of SACs. [136][137][138][139] (2) The structure of SAC does not always remain constant during the electrochemical reaction. For example, Cu single atoms could be transformed into Cu clusters during the CO 2 RR.…”

Single‐Atomic Site Catalyst with Heme Enzymes‐Like Active Sites for Electrochemical Sensing of Hydrogen Peroxide

“…[11,12] Single-atomic site catalysts (SASCs), containing exclusively isolated active metal sites, have aroused wide attention due to their specific activity and maximized atomic utilization. [13][14][15][16][17][18][19][20][21] Among them, Fe-N-C based SASCs have a large amount of Fe-N x active sites, which can mimic the structure of pentacoordinate heme iron systems in heme enzymes. [22,23] Due to these unique features, Fe-N-C based SASCs can enhance peroxidaselike catalytic activities and open new avenues to substitute the natural enzymes in the biosensing field.…”

Self‐Supporting Electrodes for Gas‐Involved Key Energy Reactions

“…In the process of CO 2 RR, CO 2 can be reduced to different products through different electron transfer pathways, including CO, HCOOH, HCHO, CH 4 , CH 3 OH, C 2 H 4 , C 2 H 5 OH, and C 3 H 7 OH; specific reaction Equations ( 10)-( 17) are as follows. [270][271][272] At present, how to prepare high-efficiency catalysts with high Faraday efficiency, low overpotential, good selectivity to the target product and high stability has become the key research and main research hotspot in the field of CO 2 RR. Similar to NRR, although great efforts have been achieved (Table 5), CO 2 RR is also at the initial research stage.…”