Synthesis And Orr Performmance Research Of Transition Metal Doped Carbon-based Materials

Oxygen reduction reaction as an important electrode reaction in fuel cells,but its sluggish kinetics rate greatly limits its long-term development.So far noble metals are regarded as the best catalysts to solve the question.However,the rare resources and high price have seriously hindered the development and large-scale applications in noble metal-based ORR catalyst.Therefore,the development of non-noble metal oxygen reduction catalysts with high performance,good stability and low price is of great significance in the practical application of fuel cells.Covalent-organic framework materials have been favored by researchers with their easy-to-control structure and large specific surface area.It has good applications in the fields of gas adsorption and molecular separation.The unique structure also provides a good help for the exposure of the active site of the catalyst and the transfer of the medium.In this paper,the doping of Transition metal elements with covalent organic framework material as the main body is used to prepare a catalyst with excellent oxygen reduction performance.The main research contents are as follows:Using Terephthalaldehyde and Melamine as the organic ligands of COPs,through the carbonization to prepare the pore structure conducive to oxygen reduction activity.Then,the Iron Phthalocyanine is supported by the Hydrothermal synthesis method,and an oxygen reduction catalyst is obtained after high-temperature carbonization.Finally,the metal doping and the carbonization temperature are adjusted to prepare the p-SNW-FePc-900 electrocatalyst with the best oxygen reduction performance.In 0.1 M KOH condition,the half-wave potential reaches 0.864 V.In the stability test,after 2,000 cycles of CV testing,the half potential of the catalyst was only negatively shifted by 0.0023 V,and its stability was comparable to commercial Pt/C.Secondly,COP-4 is selected as the main frame structure,and the Fe/Co bimetallic element is introduced into the internal structure of the material through a one-pot method,and a small amount of participation in the main structure.Which greatly improves the degree of dispersion of the active components,allowing the active sites of the catalyst to be better exposed.Moreover,the carbonization process at 900℃ also volatilizes the carbon,creating a richer pore structure and providing a good place for the catalytic oxygen reduction reaction.Through the adjustment of the metal ratio and the carbonization temperature,the performance of the catalyst is further optimized.In 0.1 M KOH condition,the catalyst showed good oxygen reduction performance,and its half-wave potential reached 0.792 V,and the catalyst catalyzes the four-electron oxygen reduction reaction,the product is only water,making it a very promising oxygen reduction electrocatalyst.Therefore,this kind of oxygen reduction catalyst based on covalent-organic framework material based on transition metal doping synthesis effectively improves the oxygen reduction catalytic activity and the stability of the catalyst through synergy.It provides ideas for the preparation of more excellent oxygen reduction electrocatalysts.