Robust Co‐Embedded Nitrogen Doped Carbon Catalyst for Oxygen Reduction Reaction in Proton Exchange Membrane Fuel Cell

Abstract

AbstractThis work reports non‐noble, cobalt embedded nitrogen doped carbon (CoNC) catalysts for oxygen reduction reaction (ORR) in Nafion‐based acidic proton exchange membrane fuel cells (PEMFCs). CoNC catalysts are synthesized through direct pyrolysis of two different zeolitic imidazolate framework (ZIF) precursors, Zn‐ZIF and Co‐ZIF. Profiting from two different precursor approach, appropriate assimilation of metal, nitrogen and carbon components is achieved which boosts oxygen reduction. Electrochemical results exemplified CoNC 3–1 catalyst derived from Zn‐ZIF:Co‐ZIF precursor in the weight ratio of 3 : 1 as the better ORR catalyst. CoNC 3–1 catalyst exhibited the highest electrochemical surface area (ECSA) (570 cm2), highest limiting current density (‐5.14 mA cm−2) and followed near 4e− reduction of oxygen revealing superior ORR activity. The catalyst also demonstrated remarkable durability with loss of only 6 % of ECSA after 30,000 cycles of accelerated durability test. The enhanced ORR activity and durability is attributed to optimal balance of Co−Nx active sites along with appropriate N contents and graphitic carbon framework.