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Downsizing porphyrin covalent organic framework particles using protected precursors for electrocatalytic CO2 reduction

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journal contribution
posted on 2024-02-26, 09:35 authored by Kenichi Endo, Asif RazaAsif Raza, Liang Yao, Samuel Van Gele, Andrés Rodríguez-Camargo, Hugo A. Vignolo-González, Lars Grunenberg, Bettina V. Lotsch

Covalent organic frameworks (COFs) are promising electrocatalyst platforms owing to their designability, porosity, and stability. Recently, COFs with various chemical structures are developed as efficient electrochemical CO2 reduction catalysts. However, controlling the morphology of COF catalysts remains a challenge, which can limit their electrocatalytic performance. Especially, while porphyrin COFs show promising catalytic properties, their particle size is mostly large and uncontrolled because of the severe aggregation of crystallites. In this work, a new synthetic methodology for rationally downsized COF catalyst particles is reported, where a tritylated amine is employed as a novel protected precursor for COF synthesis. Trityl protection provides high solubility to a porphyrin precursor, while its deprotection proceeds in situ under typical COF synthesis conditions. Subsequent homogeneous nucleation and colloidal growth yield smaller COF particles than a conventional synthesis, owing to suppressed crystallite aggregation. The downsized COF particles exhibit superior catalytic performance in electrochemical CO2 reduction, with higher CO production rate and faradaic efficiency compared to conventional COF particles. The improved performance is attributed to the higher contact area with a conductive agent. This study reveals particle size as an important factor for the evaluation of COF electrocatalysts and provides a strategy to control it.



Advanced Materials 2313197


Wiley-VCH GmbH

Other Funding information

Deutsche Forschungsgemeinschaft (DFG, German Research Foundation, Project-ID 358283783, SFB 1333), Max-Planck-Gesellschaft, Center for NanoScience (Ludwig-Maximilians-Universität München), Exzellenzclusters e-conversion (EXC 2089/1-390776260), Solar Technologies go Hybrid (SolTech, Bavarian Research Network), and Alexander von Humboldt-Stiftung. Projekt DEAL

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