Synergistic Decoration of Ultrasmall Pd NPs and Conductive Poly(3,4-ethylenedioxythiophene) Coatings on a Hydrazone Covalent Organic Framework for Boosting Ethanol Electrooxidation

Facile fabrication of nanoparticle-polymer-based catalysts with high activity and electrical conductivity is of decisive importance for their applications in electrocatalysis, yet it still faces great challenges. Herein, we reported a novel synthesis strategy for synergistically endowing a hydrazone-linked covalent organic framework (COF-42) with improved electrical conductivity and excellent catalytic activity for ethanol electrooxidation, via the idea of polymerizing the 3,4-ethylenedioxythiophene (EDOT) monomer with PdCl42– as the oxidant. The optimal products exhibit the best mass activity of 607 mA·mg–1 in comparison to the commercial Pd/C catalyst (359 mA·mg–1) and excellent operational stability from both cyclic and chronoamperometric tests in alkaline ethanol electrooxidation. Mechanistic investigations suggested that such an eminent electrocatalytic performance was obtained by the synergistic effect of porous COF-42, the conductive PEDOT coatings, and more importantly, the utmost utilization efficiency provided by highly dispersed Pd nanoparticles in/on the COF-42 matrix. This research holds great prospects toward the development of alternate electrocatalysts for direct ethanol fuel cells, and the synthetic method provided herein allows feasible synthesis of multifunctional COF materials consisting of high conductivity and activity through a simple method.