Preparation Of Sodium Ferrate By Gas Diffusion Electrode Of Fe-N-C Catalyst

Ferrite is environmental friendly oxidant with good application prospects.The traditional production methods has high energy consumption and heavy pollution,and its production difficulties limit the application of ferrate.Therefore,it is necessary to search a clean and energy-saving preparation process.Among many methods,electrolytic preparation of ferrate is an environmental friendly production method compared to other methods.In this thsis,sodium ferrate is prepared by electrolysis of self-made gas diffusion electrode in NaOH solution.Fe-N-C catalyst was prepared by pyrolysis method using dicyandiamide as nitrogen source,Fe salt as iron source,and conductive carbon black(BP2000)as carrier.The effects of pyrolysis temperature,Fe addition and other factors on the catalyst structure and ORR performance were investigated.Cyclic voltammetry,linear scanning voltammetry and other methods were used to test the catalyst oxygen reduction activity.The results show that when the pyrolysis temperature is 750 0 C and the Fe doping amount is 10%,the ORR performance of the catalyst under alkaline conditions is optimal,and its half-wave potential(0.88V)is higher than that of commercial platinum-carbon catalysts.ORR activity.The prepared Fe-N-C catalyst was mixed with graphitized carbon black(GCB),foamed nickel,isopropyl alcohol,Triton and PTFE to prepare a gas diffusion electrode.The electrode is made of foamed nickel as a substrate.Graphite carbon black(GCB),Triton and PTFE are mixed and coated on the foamed nickel.After cold pressing,an electrode diffusion layer is formed.PTFE is mixed and coated on the diffusion layer to form an electrode catalytic layer.After cold pressing and heat treatment,the electrode is hot pressed to obtain a gas diffusion electrode.XRD,contact angle,CV,LSV and other tests are performed on the electrode to characterize the electrode performance.The test results show that the ORR performance of the electrode is optimal when the hot pressing is performed at 400? for 5 minutes,and the half-wave potential reaches 0.413 V vs RHE.An electrolysis device was designed and prepared.The pure iron plate was used as the anode,and the self-made gas diffusion electrode was used as the cathode.Oxygen was continuously fed into the cathode with an oxygen flow rate of 10 mL/min.The 14M NaOH solution was used as the electrolyte for the electrolysis of sodium ferrate Preparation,after process optimization,the tank voltage can be as low as 0.96 V,which is significantly lower than the 1.84 V tank voltage of the traditional electrolytic production process,and the DC power consumption is reduced by 50%compared with the traditional process.The obvious energy-saving effect shows that the preparation method of ferrate proposed in this paper has a good application prospect.