A Molecular Copper Catalyst for Electrochemical Conversion of CO2 to C2+ Products

Abstract

Electrochemical carbon dioxide reduction (CO2RR) is a promising route to address the excessive emission of CO2 and the depletion of fossil fuels.[1] Metallic Cu and Cu-based materials have attracted increased attention, as Cu is the only metal that can reliably convert CO2 into hydrocarbons and oxygenates, such as ethanol, ethylene, and n-propanol.[2] To optimize CO2-to-C2+ conversion, considerable efforts were made to modify the catalyst composition and structure, adjusting the electrolyte, and optimizing the electrochemical setup.[3] In this context, molecular catalysts (i.e. transition metal complexes) are interesting alternatives, since the performance can be precisely tuned via ligand modification and due to the possibility for mechanistic studies at well-defined and uniform active sites.[4]Herein, a catalytic system based on an immobilized dinuclear Cu phenanthroline complex is reported that can be prepared with a straightforward synthetic method. The catalyst exhibits excellent CO2RR selectivity toward C-C coupling in aqueous electrolytes with only small production of H2. The highest Faradaic efficiency (FE) for C2+ products achieved was 62% at -1.85 V vs. Ag/AgCl with less than 10% FE for H2. Furthermore, a steady current density and a stable FE(C2H4) over 10 h continuous operation indicate a good stability of the Cu complex. In this contribution, both the electrolysis results and the relationship between structural aspects and product selectivity will be discussed, the latter based on scanning/transmission electron microscopy, X-ray photoelectron/absorption spectroscopy, and further analytical techniques.Literature:[1] X. Su, Z. Jiang, J. Zhou, H. Liu, D. Zhou, H. Shang, X. Ni, Z. Peng, F. Yang, W. Chen, Z. Qi, D. Wang, Y. Wang, Nat. Commun. 2022, 13, 1322. [2] W. Quan, Y. Lin, Y. Luo, Y. Huang, Adv. Sci. 2021, 8, e2101597. [3] J. Yu, J. Wang, Y. Ma, J. Zhou, Y. Wang, P. Lu, J. Yin, R. Ye, Z. Zhu, Z. Fan, Adv. Funct. Mater. 2021, 31. [4] D. H. Nam, P. De Luna, A. Rosas-Hernandez, A. Thevenon, F. Li, T. Agapie, J. C. Peters, O. Shekhah, M. Eddaoudi, E. H. Sargent, Nat. Mater. 2020, 19, 266.