Confining Iron Carbide Growth in Porous Carbon to Improve the Electrocatalytic Performance for Oxygen Reduction Reaction

The Fe and N co-functionalized catalyst is controllably synthesized by three-step strategy. Prussian blue (PB) and poly 2,6-diaminopyridine (PDAP) are preferentially selected to synthesize a core-shell structure attributed to their advantageous properties. Under pyrolysis process, carbonized PDAP serves as a block layer to prevent Fe-based nanoparticles from aggregation and increase the content of N. By adjusting the thickness of shell and pyrolysis temperature, the catalytic activity can be optimized. The optimized catalyst exhibits good catalytic performance in terms of onset and half-wave potentials, limiting-diffusion current density and durability. Moreover, the relationship between structure and effect is analyzed. It is found that the optimal catalyst presents excellently active for ORR stemming from a comprehensive effect, containing higher density of active site, higher surface area, porosity structure, and good conductivity of catalyst. Graphical abstract A 3D graphene-like catalyst has been controllably synthesized using core-shell and pyrolysis strategy. The morphology and activity can be tailored by adjusting the thickness of shell and pyrolysis temperature. Importantly, the optimized catalyst shows excellently active for ORR in both alkaline and acidic media.