Rational design of porous Fex-N@MOF as a highly efficient catalyst for oxygen reduction over a wide pH range

The oxygen reduction reaction (ORR) kinetics are well known to strongly rely on the activives of electrocatalysts . Herein, a Fe-N-doped porous carbon-based electrocatalyst combined with zinc (Zn) -based metal-organic frameworks (MOFs) (Fe x -N@MOF) was designed and successfully fabricated via a facile process combined immersion doping and pyrolysis. By controlling the formation of Fe 3 C, the physical structure of porous carbon was significantly altered, and the active chemical sites of Fe species can be formed to catalyze ORR. The uniform N-doped three-dimensional interpenetrating network structure yielded a high surface area. Both Fe 3 C and Fe-N x could offer an abundance of active sites and thus promoted Fe 0.05 -N@MOF to exhibit high ORR activity in alkaline, neutral and acid electrolytes. Fe 0.05 -N@MOF showed extraordinary stability and methanol tolerance under a varied pH range conditions, it could be applied as cathode electrocatalyst in different fuel cells such as Zn-air fuel cell (ZFC), microbial fuel cells (MFCs), as well as direct methanol fuel cell (DMFC). Fe 0.05 -N@MOF is a promising material to replace Pt-based electrocatalysts as non-precious metal catalysts.