Bio-inspired chitosan-heme-vitamin B12-derived Fe–Co bimetallic-doped mesoporous carbons for efficiently electro-activating oxygen†
Abstract
A bio-inspired bimetallic Fe- and Co-doped nitrogen–carbon material (Fe–Co–N–C) was synthesized using chitosan and porphyrin-like heme and vitamin B12 precursors. Anionic heme with Fe–N4 moieties and vitamin B12 with Co–N4 moieties were grafted onto the surface of acidic chitosan polymers through interactions with cationic –NH3+, and these polymers were coated onto nano-sized silica spheres to form the composite precursors. The optimised thermolysis of these composites yielded mesoporous carbons with abundant surface Fe–Nx and Co–Nx sites. The as-prepared Fe–Co–N–Cs catalyzed the oxygen reduction reaction (ORR) in both alkaline and acidic conditions. It not only provided a low-cost bio-inspired synthesis for bimetal-doped carbons using biologics with the definitive molecular structure but also the as-prepared mesoporous Fe–Co–N–Cs represented as the possible NPMC candidates for replacing Pt-based electrocatalysts in fuel cells.