Preparation And Oxygen Reduction Properties Of Iron Based Nanomaterials

Fuel cells are currently the energy devices with the best development prospects.They are clean and efficient,have almost no pollution to the global environment,and can replace traditional fossil fuels to alleviate energy scarcity and environmental pollution.They can replace traditional fossil fuels to alleviate energy scarcity and environmental pollution.However,the oxygen reduction reaction（ORR）kinetics process of the fuel cell cathode is slow and needs to be enhanced by commercialized Pt/C.Because of scarce reserves,poor stability and methanol resistance,Pt/C catalysts limit the large-scale use of fuel cells.Therefore,exploring the low-cost,high-efficiency and stable ORR catalyst to replace commercialized Pt/C has become the focus of today’s research.This thesis is based on the non-noble metal Fe element and used a simple method to prepare Fe/N-doped carbon materials.Its ORR performance is better than that of commercially available Pt/C.It is one of the promising non-noble metal electrocatalysts today.The main research contents are as follows:（1）Fe₃O₄ nanoparticles supported N-doped carbon hollow nanospheres:Using silica as a sacrificial template,synthesis of Fe₃O₄ nanoparticles supported N-doped carbon hollow nanospheres（5-Fe/NC-HNS-900）.The BET surface area（1063.9 m2 g-1）of the catalyst 5-Fe/NC-HNS-900 is larger than that of NC-HNS-900（974.6 m2 g-1）,and it has a rich mesoporous structure,which promotes the effective transportation of ORR-related species and expose more active sites.The synergy between Fe₃O₄nanoparticles and doped nitrogen greatly improves the ORR performance of the catalyst5-Fe/NC-HNS-900（Half-wave potential is 0.87 V）.In addition,the catalyst also has excellent stability and ability to withstand methanol.（2）Carbon nanotube entangled Fe,N-doped carbon nanocomposite:We designed a simple in-situ pyrolysis method to synthesize carbon nanotube entangled Fe,N-doped carbon nanocomposite（Fe@NC-ZM）.The catalyst Fe@NC-ZM has a large BET surface area（276.2 m2 g-1）,rich mesoporous characteristics,Fe,N doping and the synergy between various species can expose more active sites,and promote conductivity and mass transfer.Benefiting from the above unique advantages,Fe@NC-ZM has excellent ORR performance(E_1/2=0.82 V),which has a more positive potential than commercially available Pt/C(E_1/2=0.81 V).