Synthesis of Co3Fe7/CoFe2O4 incorporated porous carbon catalysts via molten salt method: applications in the oxygen reduction reaction and 4-nitrophenol reduction.

Developing high-performance, multifunctional non-precious metal catalysts is essential for enhancing the efficiency of future energy utilization. In this study, four types of magnetic, recyclable Co3Fe7/CoFe2O4 incorporated porous carbon composite catalysts were synthesized using citric acid as the carbon source and ammonium chloride (NH4Cl) as the salt medium. Iron and cobalt salts, in four different proportions, were uniformly incorporated using freeze-drying technology and subsequently processed through in situ calcination. Among the synthesized catalysts, Co3Fe7/CoFe2O4@NC-1, demonstrated outstanding catalytic reduction performance, with a reaction rate constant (k) of 0.031 min-1, along with excellent cycle stability for 4-NP. The resulting Co3Fe7/CoFe2O4@NC-3 catalyst exhibited good ORR activity in an alkaline medium (E onset = 0.99 V, E 1/2 = 0.83 V, J L = -5.2 mA cm-2), along with long-term durability and resistance to methanol poisoning. These hybrid materials hold promise as non-precious metal electrocatalysts for fuel cell ORRs and introduce a new class of catalytic candidates for 4-NP reduction.