Orthogonal Design of Fe−N₄ Active Sites and Hierarchical Porosity in Hydrazine Oxidation Electrocatalysts

Hydrazine is a promising energy-dense fuel for alkaline fuel cells. To design efficient and affordable electrocatalysts for the hydrazine oxidation reaction (HzOR), one needs to control both the active site and the supporting scaffold. We now report a family of electrocatalysts for alkaline HzOR, consisting of atomically dispersed Fe−N₄ sites (as iron corroles of varying sizes) on hierarchically porous, electronically conductive carbon scaffolds that were prepared by self-templating from a novel barium-based precursor. The orthogonal design of active sites and flow-enhancing scaffolds allowed the rational optimization of their combination, to achieve excellent HzOR activity. These catalysts demonstrate the utility and versatility of metallocorroles for electrocatalysis in the nitrogen cycle, as well as the importance of pore tuning for optimization of the current density.