Template Conversion of Covalent Organic Frameworks into 2D Conducting Nanocarbons for Catalyzing Oxygen Reduction Reaction

Abstract

Progress over the past decades in porous materials has exerted great effect on the design of metal-free carbon electrochemical catalysts in fuel cells. The carbon material must combine three functions, i.e., electrical conductivity for electron transport, optimal pores for ion motion, and abundant heteroatom sites for catalysis. Here, an ideal carbon catalyst is achieved by combining two strategies—the use of a 2D covalent organic framework (COF) and the development of a suitable template to guide the pyrolysis. The COF produces nanosized carbon sheets that combine high conductivity, hierarchical porosity, and abundant heteroatom catalytic edges. The catalysts achieve superior performance to authentic Pt/C with exceptional onset potential (0 V vs −0.03 V), half-wave potentials (−0.11 V vs −0.16 V), high limit current density (7.2 mA cm⁻² vs 6.0 mA cm⁻²), low Tafel slope (110 mV decade⁻¹ vs 121 mV decade⁻¹), long-time stability, and methanol tolerance. These results reveal a novel material platform based on 2D COFs for designing novel 2D carbon materials.

Two-dimensional nanosized carbon materials are made by a new strategy in which 2D covalent organic frameworks (COFs) are used as precursors in conjunction with a template carbonization methodology. This strategy enables the production of 2D carbons that combine high conductivity, hierarchical porosity, and abundant edge active sites, and that achieve exceptional catalytic activity in oxygen reduction reaction.

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