Synthesize Transition Metal Complexes-CoFe₂O₄as Non-noble Cathode Catalysts For Fuel Cell

Fuel cell has attracted much attention due to the high power density and lowemissions, because of the superior performance that it has been recognized as the mostsuitable for portable and stationary applications. However, commercialization of fuelcell is seriously hindered by using the Pt/C catalyst which led to high cost. For now, theincrease of Pt dispersion and utilization, the development of alternative non-noble metalcatalyst are the key to solving the obstacles. In this paper, the transition metal oxidesCoFe₂O₄was prepared as non-precious metal catalysts and the electrochemicalproperties were explored. In the meanwhile, the CoFe₂O₄/CPANI catalyst wassynthesized which using polyaniline as a nitrogen source mixed with CoFe₂O₄, afterheating treatment it displayed good activity and stability.The CoFe₂O₄was prepared via the mild hydrothermal synthesis method. XRD andSEM characterization results show that the CoFe₂O₄was pure, calculated by Scherrerformula, the mean particle size of CoFe₂O₄was15nm²5nm; cyclic voltammetry （CV）and linear sweep （LSV） experiment show that both CoFe₂O₄and of CoFe₂O₄/Ccatalysts have electrochemical activity in0.1M KOH, the catalytic activity ofCoFe₂O₄/C was better due to the incorporation of the Vulcan XC-72carbon, that it canget an effective three-phase interface. After heating treatment, it would improve theoxygen reduction onset potential, which is due to the heat treatment enhancedsynergistic between CoFe₂O₄and carbon, the best oxygen reduction activity obtained inthe experiment is that the CoFe₂O₄: C was2:1, under400℃, the oxygen reductionpotential was very close to that of JM Pt/C catalyst; rotating disc electrode （RDE）experiment results show that CoFe₂O₄/C catalyst has excellent catalytic activity and theelectron transfer number was close to four during oxygen reduction process.In this paper, the CoFe₂O₄was mixed with polyaniline forming of complexes, andthen after heat treatment, the CoFe₂O₄/CPANI catalyst was got. EDS spectrum and SEMcharacterization results show that the catalysts were pure, Oxygen reduction activitytests proved that catalysts had electrochemical activity under acidic conditions, theonset potentials of CoFe₂O₄/CPANI catalyst was0.86V （vs. RHE） which was smallerthan that of JM Pt/C catalyst, therefore it needs to be further improved. The rotatingdisk electrode experiments （RDE） results show that the oxygen reduction reaction is afour-electron transfer process, the apparent reaction equation is: O₂+4H⁺+4e^-=2H₂O; catalyst stability experiment show that after800circles cyclic voltammetry（CV）,CoFe₂O₄/CPANI catalyst maintains good electrochemical stability, whileelectrochemical activity of JM Pt/C catalyst attenuation extremely fast in800circles,linear sweep test of the catalysts before and after800circles also show thatCoFe₂O₄/CPANI catalyst oxygen reduction ability didn’t reduce too much, but thecatalytic ability of JM Pt/C catalyst has been a marked decline, therefore, theCoFe₂O₄/CPANI catalyst has better electrochemical stability.