Synergy between iron oxide sites and nitrogen-doped carbon xerogel/diamond matrix for boosting the oxygen reduction reaction

Abstract

The innovative design and facile synthesis of efficient and stable electrocatalysts for the oxygen reduction reaction (ORR) are crucial in the field of fuel cells. Herein, the facile synthesis of an iron oxide@nitrogen-doped carbon diamond (FeO_x@NCD) composite via an effective pyrolysis strategy is reported. The properties of this electrocatalyst, including a high density of active sites, nitrogen doping, accessible surface area, well dispersed pyramidal morphology of the iron oxide, and the porous structure of the carbon matrix, promote a highly active oxygen reduction reaction (ORR) performance. The electrocatalyst exhibits outstanding stability, with a half-wave potential of 0.692 V in alkaline solution (0.1 M KOH), as well as a limiting current density of −31.5 mA cm⁻² at 0.17 V vs. RHE. This study highlights the benefits of hybridizing sp² carbon xerogel and sp³ diamond carbon allotropes with iron oxide to boost the ORR activity. The proposed strategy opens up an avenue for designing advanced carbon-supported metal oxide catalysts that exhibit excellent electrocatalytic performance.