Bioinspired self-assembled Fe/Cu-phenolic building blocks of hierarchical porous biomass-derived carbon aerogels for enhanced electrocatalytic oxygen reduction

Abstract

Biomass-derived metal/carbon hybrid functional materials are considered to be highly promising electrocatalysts for oxygen reduction reactions (ORR). This is because of the desirable properties that they offer, including their complex microarchitectures，low costs，and feasibility of large scale production. In this work, we report a bottom-up synthesis of an economical, highly-active, and stable ORR electrocatalyst -- Fe/Cu-phenolic supramolecule decorated hierarchical porous biomass-derived N-self-doped carbon aerogel. With our method of thermal carbonization of bimetallic polyphenol networks functionalized collagen/cellulose nanocrystals (Col/CNCs), this material is shown to have a large number of storage sites and enhanced diffusion kinetics for optimal electrocatalytic oxygen reduction. Thanks to the rich active functional groups of Col/CNCs, along with the interfacial adhesion ability of plant polyphenols, we successfully synthesized a group of carbon aerogel composites loaded with metal nanoparticles. Benefiting from the fractal structure of the natural building blocks, the as-synthesized FexCuy/CCol-CNCA presents a hierarchical porous structure, exquisite aerogel morphology and a heteroatom composition. With these advantages, it is demonstrated to have higher durability and better electrocatalytic ORR performance than the commercial 20% Pt/C.