Preparation And Cathode Performance Of Nitrogen And Phosphorus Dual-doped Carbon Derived Biomass

Microbial fuel cell（MFC）is a new type of electricity generating device that uses anode microorganisms as electricity generating bacteria and undergoes metabolic reactions to convert chemical energy into electrical energy in sewage.The single-chamber air cathode MFC has the advantages of simple structure,pollution-free cathode products,and fast mass transfer.In addition,it directly uses oxygen in the air as the cathode electron acceptor,and has low cost.Recently,it has received extensive attention.However,the low-rate oxygen reduction reaction at the cathode restricts the output and practical application of MFC.Therefore,the development of high-efficiency cathode catalysts is very important for improving the power generation efficiency of MFC.After the widespread application of Pt-based catalysts and metal oxide catalysts,biomass carbon-based catalysts have attracted researchers’attention due to their low cost and abundant reserves.In this paper,firstly,used biomass waste durian shell as raw material,（NH₄）₃PO₄·3H₂O as doping source,and introduced two non-metallic elements,N and P,N/P co-doped oxygen reduction catalyst NPDC was prepared.Optimized the calcination temperature and discuss the influence of temperature on the material structure and electrocatalytic performance.The CV and LSV curves in different test environments showed that NPDC-900 had a larger limiting current,half-wave potential and onset potential compared to the catalysts NPDC-800 and NPDC-1000.So,it had excellent ORR catalytic performance.The self-made carbon-based catalyst DC-900 and commercial 20%Pt/C were selected to test the influence of the binder Nafion dosage and catalyst loading on its oxygen reduction characteristics.Secondly,the prepared catalyst NPDC-900 was compared with the single heteroatom-doped catalysts NDC-900 and PDC-900 to discuss the oxygen reduction activity of the nitrogen and phosphorus co-doped catalysts.The experimental results showed that the catalyst NPDC-900 had a large amount of mesoporous structure,and the specific surface area（1264 m²/g）.It was predicted that the catalyst has high active site utilization and excellent mass transfer efficiency.ORR test in a neutral environment showed that the half-wave potential(E_1/2)of NPDC-900 was 0.55 V,the limiting current（J_L）was 5.91 m A/cm²,and the onset potential(E_onset)was 0.98 V,which was better than other carbon-based catalysts.The performance was similar to that of commercial Pt/C.In the ORR test under alkaline environment,NPDC-900 also had excellent ORR activity.Which explained the applicability of NPDC-900 in different p H sewage.In addition,the RRDE test showed that the electron transfer number of the catalyst NPDC-900 is close to4,and the ORR process belonged to the 4e^-pathway.Chronoamperometry tests show that NPDC-900 has better long-term stability than Pt/C,and can still maintain 96%of its initial current density after 12000 s of operation.When the cathode catalyst was applied to a microbial fuel cell,the maximum power density was 560.27±13 m W/m²,and the starting voltage was 0.40 V.