Organic frameworks confined Cu single atoms and nanoclusters for tandem electrocatalytic CO₂ reduction to methane

Abstract

The electrochemical reduction reaction of carbon dioxide (CO2RR) is considered to be an effective way to realize carbon neutrality. As a type of intensively studied materials, covalent organic frameworks (COFs) with a tunable pore structure and various functional groups are promising catalysts for CO2RR. Herein, COF synthesized by 2,6‐diaminoanthraquinone and 2,4,6‐triformylphloroglucinol is employed to assist the synthesis of electrocatalysts from Cu single atoms (SAs) to nanoclusters by controlling the electrodeposition. A tandem catalyst for CO2‐to‐CH4 conversion is thus achieved by the Cu nanoclusters dispersed among the isolated Cu SAs in the COF network. It is proposed that CO2 is first reduced to CO over the atomically isolated Cu SAs, followed by diffusion onto the neighboring Cu nanoclusters for further reduction into CH4. In addition, mechanistic analysis suggests that the coordinated K+ ions on the COF network promote the activation of CO2 and the adsorption of reaction intermediates, thus realizing the suppressed hydrogen evolution reaction and selective production of CH4. This study presents a new insight of COFs for the confined synthesis of a tunable SA to nanocluster electrocatalysts, disclosing the great potential of COFs in electrocatalysis.

Engineering Single-Atom Active Sites on Covalent Organic Frameworks for Boosting CO2 Photoreduction

“…First, Fe SAS/Tr-COF photocatalysts with atomically dispersed Fe atoms can expose abundant metal active sites to effectively capture CO 2 molecules. Second, the formed Fe–N charge bridge in Fe SAS/Tr-COFs can provide an additional channel for further ultra-fast electron migration from Tr-COF units to atomically dispersed Fe centers, thus achieving the long-life carrier separation. ,− Third, the absorbed CO 2 could be effectively reduced to the CO product on the Fe SAS/Tr-COF catalyst.…”

Atomic‐Level Pt Electrocatalyst Synthesized via Iced Photochemical Method for Hydrogen Evolution Reaction with High Efficiency

“…The high‐magnification HAADF‐STEM images can more intuitively display the dispersion of metal atoms on the carrier. [ 12 ] The Pt atoms of Pt‐SA@HG were corroborated to be uniformly dispersed on the carrier with isolated bright dots (Figure 1e). However, in samples Pt‐Clu@HG and Pt‐Nc@HG, Pt elements have obvious aggregation (Figure 1f,g, Figures S4 and S5, Supporting Information).…”

Cu‐Based Organic‐Inorganic Composite Materials for Electrochemical CO2Reduction

“…Recently, Shao and co-workers prepared Cu single atoms (SAs) to nanoclusters (NCs) electrocatalysts confined by a conductive 2D COF structure by electrodeposition. [182] The resulting NCs-SAs Cu/COF electrocatalyst exhibited the highest FE CH4 (56.2% � 5%) at the potential of À 1.26 V vs. RHE. They found that the electrodeposited Cu NCs were distributed around the Cu SAs.…”

“…With the changes of the working potentials, the Cu clusters depolymerized into Cu 2+ and most of the stripped Cu 2+ was re‐anchored by CTF−B due to the strong Cu‐bipyridine interaction, thus reforming the CTF−Cu structure. Recently, Shao and co‐workers prepared Cu single atoms (SAs) to nanoclusters (NCs) electrocatalysts confined by a conductive 2D COF structure by electrodeposition [182] . The resulting NCs‐SAs Cu/COF electrocatalyst exhibited the highest FE CH4 (56.2% ±5%) at the potential of −1.26 V vs. RHE.…”