Modulating carbon dioxide activation on carbon nanotube immobilized salophen complexes by varying metal centers for efficient electrocatalytic reduction

Xiaofeng Cui; Shuyan Liu; Lijun Zhao; Jinfa Yu; Shan Ling; Yingguo Zhao; Junwei Wang; Wei Qin; Xiaoxia Mao; Jianli Zhang

doi:10.1016/j.jcis.2021.10.048

Modulating carbon dioxide activation on carbon nanotube immobilized salophen complexes by varying metal centers for efficient electrocatalytic reduction

J Colloid Interface Sci. 2022 Feb 15;608(Pt 2):1827-1836. doi: 10.1016/j.jcis.2021.10.048. Epub 2021 Oct 14.

Authors

Xiaofeng Cui¹, Shuyan Liu², Lijun Zhao², Jinfa Yu², Shan Ling², Yingguo Zhao³, Junwei Wang², Wei Qin², Xiaoxia Mao², Jianli Zhang⁴

Affiliations

¹ Anhui Key Laboratory of Photoelectric-Magnetic Functional Materials, School of Chemistry and Chemical Engineering, Anqing Normal University, Anqing, Anhui 246011, PR China. Electronic address: xfcui@aqnu.edu.cn.
² Anhui Key Laboratory of Photoelectric-Magnetic Functional Materials, School of Chemistry and Chemical Engineering, Anqing Normal University, Anqing, Anhui 246011, PR China.
³ Anhui Key Laboratory of Photoelectric-Magnetic Functional Materials, School of Chemistry and Chemical Engineering, Anqing Normal University, Anqing, Anhui 246011, PR China. Electronic address: zhaoyg@aqnu.edu.cn.
⁴ State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering, Ningxia University, Yinchuan 750021, PR China.

PMID: 34742091
DOI: 10.1016/j.jcis.2021.10.048

Abstract

Electrocatalytic CO₂ reduction (ECR) into valuable chemicals, especially driven by renewable energy, presents a promising pattern to realize carbon neutrality. Site-isolated metal complexes flourish in the area of ECR as single-atom-like catalysts because of their competent and tailorable activity. In this study, salophen-based metal (Fe, Co, Ni and Cu) complexes were anchored onto carbon nanotubes (CNTs) to construct efficient catalysts for electrochemically converting CO₂ to CO. Both experimental and theoretical results verified that CO₂ activation was the rate-determining step for the catalytic performance of these hybrid molecular catalysts. The coordinate activation ability can be manipulated by varying the metal centers. The as-synthesized Fe-salophen hybrid CNT (Fe-salophen/CNT) shows the best activity and selectivity of -13.24 mA·cm^-2 current density with 86.8% Faradaic efficiency for generating CO (FE_CO) at -0.76 V vs. RHE in aqueous solution, whereas Cu-salophen/CNT only achieved a -2.22 mA·cm^-2 current density and 57.9% FE_CO under the same reaction conditions. These distinct catalytic performances resulted from the different coordination activation abilities of CO₂ on various metal centers.

Keywords: CNT immobilizing; Electrocatalytic CO(2) reduction; Metal center; Salophen-based complexes.