Organic frameworks confined Cu single atoms and nanoclusters for tandem electrocatalytic CO<sub>2</sub> reduction to methane
Qinglan Zhao, Yian Wang, Meng Li, Shangqian Zhu, Tiehuai Li, Jixiang Yang, Ting Lin, Ernest Pahuyo Delmo, Yinuo Wang, Juhee Jang, Meng Gu, Minhua Shao
Abstract
Abstract The electrochemical reduction reaction of carbon dioxide (CO 2 RR) 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 CO 2 RR. 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 CO 2 ‐to‐CH 4 conversion is thus achieved by the Cu nanoclusters dispersed among the isolated Cu SAs in the COF network. It is proposed that CO 2 is first reduced to CO over the atomically isolated Cu SAs, followed by diffusion onto the neighboring Cu nanoclusters for further reduction into CH 4 . In addition, mechanistic analysis suggests that the coordinated K + ions on the COF network promote the activation of CO 2 and the adsorption of reaction intermediates, thus realizing the suppressed hydrogen evolution reaction and selective production of CH 4 . 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.