Modulating the Density of Catalytic Sites in Multiple-Component Covalent Organic Frameworks for Electrocatalytic Carbon Dioxide Reduction

Minghao Liu; Xingyue Zhao; Shuai Yang; Xiubei Yang; Xuewen Li; Jun He; George Zheng Chen; Qing Xu; Gaofeng Zeng

doi:10.1021/acsami.3c10802

Modulating the Density of Catalytic Sites in Multiple-Component Covalent Organic Frameworks for Electrocatalytic Carbon Dioxide Reduction

ACS Appl Mater Interfaces. 2023 Sep 20;15(37):44384-44393. doi: 10.1021/acsami.3c10802. Epub 2023 Sep 6.

Authors

Minghao Liu^{1

2}, Xingyue Zhao¹, Shuai Yang¹, Xiubei Yang^{1

3}, Xuewen Li^{1

3}, Jun He^{2

4}, George Zheng Chen⁵, Qing Xu^{1

3}, Gaofeng Zeng^{1

3}

Affiliations

¹ CAS Key Laboratory of Low-Carbon Conversion Science and Engineering, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China.
² Department of Chemical and Environmental Engineering, University of Nottingham Ningbo China, Ningbo 315199, China.
³ School of Chemical Engineering, University of Chinese Academy of Sciences, Beijing 100049, China.
⁴ Nottingham Ningbo China Beacon of Excellence Research and Innovation Institute, Ningbo 315100, China.
⁵ Department of Chemical and Environmental Engineering, University of Nottingham, Nottingham NG7 2RD, U.K.

PMID: 37672678
DOI: 10.1021/acsami.3c10802

Abstract

It is generally assumed that the more metal atoms in covalent organic frameworks (COFs) contribute to higher activity toward electrocatalytic carbon dioxide reduction (CO₂RR) and hindered us in exploring the correlation between the density of catalytic sites and catalytic performances. Herein, we have constructed quantitative density of catalytic sites in multiple COFs for CO₂RR, in which the contents of phthalocyanine (H₂Pc) and nickel phthalocyanine (NiPc) units were preciously controlled. With a molar ratio of 1/1 for the H₂Pc and NiPc units in COFs, the catalyst achieved the highest selectivity with a carbon monoxide Faradaic efficiency (FE_CO) of 95.37% and activity with a turnover frequency (TOF) of 4713.53 h^-1. In the multiple H₂Pc/NiPc-COFs, the electron-donating features of the H₂Pc units provide electron transport to the NiPc centers and thus improved the binding ability of CO₂ and intermediates on the NiPc units. The theoretical calculation further confirmed that the H₂Pc units donated their electrons to the NiPc units in the frameworks, enhanced the electron density of the Ni sites, and improved the binding ability with Lewis acidic CO₂ molecules, thereby boosting the CO₂RR performance. This study provides us with new insight into the design of highly active catalysts in electrocatalytic systems.

Keywords: alternate structure; carbon dioxide reduction reaction; covalent organic frameworks; phthalocyanine; structure−property correlation.