Complementary Operando Spectroscopy identification of in-situ generated metastable charge-asymmetry Cu2-CuN3 clusters for CO2 reduction to ethanol

Abstract

Copper-based materials can reliably convert carbon dioxide into multi-carbon products but they suffer from poor activity and product selectivity. The atomic structure-activity relationship of electrocatalysts for the selectivity is controversial due to the lacking of systemic multiple dimensions for operando condition study. Herein, we synthesized high-performance CO2RR catalyst comprising of CuO clusters supported on N-doped carbon nanosheets, which exhibited high C2+ products Faradaic efficiency of 73% including decent ethanol selectivity of 51% with a partial current density of 14.4 mA/cm−2 at −1.1 V vs. RHE. We evidenced catalyst restructuring and tracked the variation of the active states under reaction conditions, presenting the atomic structure-activity relationship of this catalyst. Operando XAS, XANES simulations and Quasi-in-situ XPS analyses identified a reversible potential-dependent transformation from dispersed CuO clusters to Cu2-CuN3 clusters which are the optimal sites. This cluster can’t exist without the applied potential. The N-doping dispersed the reduced Cun clusters uniformly and maintained excellent stability and high activity with adjusting the charge distribution between the Cu atoms and N-doped carbon interface. By combining Operando FTIR and DFT calculations, it was recognized that the Cu2-CuN3 clusters displayed charge-asymmetric sites which were intensified by CH3* adsorbing, beneficial to the formation of the high-efficiency asymmetric ethanol.

Electrocatalytic CO2 reduction to alcohols by modulating the molecular geometry and Cu coordination in bicentric copper complexes

“…24, Table 4), underlining its small cluster size and highly under-coordinated nature that correspond to the Cs-TEM observation. The Cu-N/O coordination at R = 1.5 Å is persistent throughout the whole testing period, confirming that not all Cu centers are stripped off from the complex 32 . This is in line with the MS, UV-Vis, and XPS observations that collectively point to the coexistence of both metallic Cu species and incompletely reduced Hex-2Cu-O complexes under the CO 2 RR condition.…”

Rational design, application and dynamic evolution of Cu–N–C single-atom catalysts

“…This will restrict the elaboration and understanding of the mechanism and essence of catalytic reactions. 59,107,196 The dynamic reconstruction of isolated active sites is often involved in the application of Cu–N–C SAC systems. This dynamic evolution takes place in the reaction process and can return to the original state after the reaction.…”

“…58 In 2022, Su et al combined a variety of in situ characterization methods to deeply explore the real active sites of Cu–N–C SACs under the working potential, which is conducive to clarifying the real pathway of the reaction process. 59 In conclusion, the research on Cu–N–C SACs systems is still challenging, and thus it is necessary for us to systematically summarize the reports in recent years to highlight the direction for follow-up research.…”

Atomically distributed asymmetrical five-coordinated Co–N5 moieties on N-rich doped C enabling enhanced redox kinetics for advanced Li–S batteries

“…3e–l) in CoN5 SA/NC with asymmetrical Co–N 5 . 49,50 The Gibbs free energy profiles (Fig. 6c) can further reveal the sulphur reduction reaction process of each conversion step from S 8 to Li 2 S on the NC and CoN5 SA/NC surfaces (Fig.…”