Design Of Iron Cobalt Based Nitrogen Phosphorus Sulphur Doped Core Shell Micropheres And Its Application As Multifunctional Catalysts

Zinc-Air battery is a good energy conversion device,but the high price and poor stability of cathode catalyst limit its wide application.Organic dyes in water environment are the main pollutants.Due to the lack of suitable catalyst,the degradation efficiency of organic dyes is very low.Therefore,the design and synthesis of multifunctional catalyst with low cost,good electrochemical activity and high catalytic degradation efficiency of organic pollutants is of great significance.In this paper,Fe3O4@PZS@ZIF-67 was used as precursor,and the microspheres obtained after carbonization,acid etching and second carbonization were used as the multifunctional catalysts to study the electrochemical catalysis performance and their catalytic performance for organic dye degradation.In this paper,Fe3O4@PZS@ZIF-67 core-double shell template was synthesized.The composition and structure of the microspheres were studied during carbonized,acid etching and second carbonization.The results shows that Fe3O4/Co-NPS microspheres encapsulated Fe nanoparticles are formed after carbonization,Fe/Co-NPS porous carbon spheres encapsulated Fe3P and Co2P are obtained after acid etching,and FeCo@C MS microspheres with Fe,Co2P and Fe3P crystal particles as cores are produced after second carbonization.The element composition and state of Fe3O4/Co-NPS,Fe/Co-NPS and FeCo@C MS microspheres was changed.The microspheres all had mesoporous structure,and the bet specific surface area and pore volume were changed.The oxygen reduction reaction performance of FeCo@C MS in alkaline solution is better,with the initial potential(Eo)of 1.04 V,the half-wave potential(E1/2)of 0.85 V,close to commercial Pt/C catalyst(Eo:1.02 V,E1/2:0.86 V).The stability and the resistance to methanol are good.FeCo@C MS also shows good oxygen evolution reaction performance.The oxygen reduction reaction performance of FeCo@C MS in acid solution is good.FeCo@C MS shows good hydrogen reduction reaction performance,when the current density was 10 mA cm-2,the overpotential is 0.22 V,tafel slope is 66 mv dec-1 and impedance is 19.26 Ω.After electrolysis for 12 h,the voltage dropped only 29 mV,which shows the stability is good.The open-circuit voltage of the Zinc-Air battery using FeCo@C MS as cathode catalyst is 1.34 V.The maximum power density is 86.09 mW cm-2 and the specific capacity and energy density reach 503 mAh g-1zn and 639 Wh kg-1Zn,respectively.The battery with FeCo@C MS has a better charge-discharge cycling durability.Fe3O4/Co-NPS is an effective catalyst for RhB degradation.RhB can be degraded completely within 18 min,and FeCoOx and FeCoPx are the active sites of RhB degradation.The carbon shell doped with hetero atom plays an important role in RhB degradation.Fe3O4/Co-NPS also has good catalytic efficiency for BB and MB.S04·-is the main radical species in the catalytic system.After five cycles of Fe3O4/Co-NPS,RhB can still be fully degraded in 30 minutes and Fe3O4/Co-NPS can be reused.