Designed self-assembly of iron encapsulated doped porous carbon as durable electrocatalyst for oxygen reduction reaction in alkaline medium

Abstract

A probable pore-formation mechanism of self-assembled doped porous carbon has been proposed. Hydrogen-bonding interaction between different precursors plays a crucial role in determining the porous morphology. The high specific surface area of porous carbon network consists of an abundant number of mesopores as well as micropores which promote the enhanced diffusion of ions and further reduce the mass transfer losses by increasing the number of triple phase boundaries (TPBs). Encapsulation of iron particles within the porous framework not only preserves the intrinsic catalytic properties of the metal also enhances the durability of the catalyst. Iron incorporation in nitrogen (N), boron (B) and co-doped porous carbon predominantly improves the reaction kinetics compared to metal-free catalysts in terms of onset potential and current density. Iron incorporated N and B co-doped porous carbon (Fe/NBPC) has exhibited an onset potential of −0.12 V vs SCE with low peroxide yield of 12%. Comprehensive theoretical analysis based on net charge transfer and total density of states reveal the superiority of co-doping. Present work validates multi-element doped carbon network can be considered as a promising replacement of Pt-based catalysts for fuel cells in alkaline medium.