Electrocatalytic, Kinetic, and Mechanism Insights into the Oxygen‐Reduction Catalyzed Based on the Biomass‐Derived FeO<i>_x</i>@N‐Doped Porous Carbon Composites

Abstract

Abstract A valid strategy for amplifying the oxygen reduction reaction (ORR) efficiency of non‐noble electrocatalyst in both alkaline and acid electrolytes by decorated with a layer of biomass derivative nitrogen‐doped carbon (NPC) is proposed. Herein, a top‐down strategy for the generally fabricating NPC matrix decorated with trace of metal oxides nanoparticles (FeO x NPs) by a dual‐template assisted high‐temperature pyrolysis process is reported. A high‐activity FeO x / FeNC (namely Hemin/NPC‐900) ORR electrocatalyst is prepared via simply carbonizing the admixture of Mg 5 (OH) 2 (CO 3 ) 4 and NaCl as dual‐templates, melamine and acorn shells as nitrogen and carbon source, hemin as a natural iron and nitrogen source, respectively. Owing to its unique 3D porous construction, large BET areas (819.1 m 2 ∙g −1 ), and evenly dispersed active sites (FeN x , CN, and FeO parts), the optimized Hemin/NPC‐900 catalyst displays comparable ORR catalytic activities, remarkable survivability to methanol, and preferable long‐term stability in both alkali and acid electrolyte compared with benchmark Pt/C. More importantly, density function theory computations certify that the interaction between Fe 3 O 4 nanoparticles and arm‐GN (graphitic N at armchair edge) active sites can effectually promote ORR electrocatalytic performance by a lower overpotential of 0.81 eV. Accordingly, the research provides some insight into design of low‐cost non‐precious metal ORR catalysts in theory and practice.

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