Fe-N catalyst derived from and supported on Lycopodium clavatum sporopollenin exine capsules for the oxygen reduction reaction.

A carbon-supported electrocatalyst, featuring carbon nanotubes anchored on 3D porous graphitic carbon, was developed with the aim to perform in the operating conditions of alkaline fuel cells and metal air batteries. The catalyst was developed via two steps: first powders of Sporopollenin exine capsules used as a bio-based carbon support were activated via CO gasification to obtain a high specific area and porosity, second the derived porous carbons were impregnated by an iron salt and a nitrogen source, to be carbonised in Nitrogen at high temperature. The prepared catalyst demonstrated an efficient oxygen reduction reaction activity showing a half-wave potential of ~ 0.775 V vs. Reversible hydrogen electrode, comparable with that of commercial 20 wt% Pt/C in alkaline conditions, a good stability after accelerated degradation testing, retaining ~ 86% of the initial limiting current density, and a higher diffusion limited current density (6.3 vs. 5.1 mA cm) than the commercial counterpart. Overall, we show the suitability of Sporopollenin exine capsule as support for electrocatalysis and a promising methodology to develop sustainable catalysts for the oxygen reduction reaction.