Preparation And Properties Of Heteroatom-doped Carbon Materials For Electrocatalytic

Fuel cells and metal/air batteries are considered as potential alternatives to fossil energy due to their environmental friendliness,high energy density,and low energy consumption.As their important reactions,oxygen reduction reaction（ORR）and oxygen evolution reaction（OER）have the defects of complex reaction pathways and slow kinetics,which severely restrict the efficiency of these devices.At present,precious metals such as platinum and ruthenium dioxide are considered to be the most effective ORR and OER catalysts,however,due to its high price and poor stability,it is not conducive to the large-scale commercial application of fuel cells Therefore,it is urgent to develop cheap and high-performance catalysts.Nowadays,carbon materials have become a research hotspot because of their low cost,good conductivity and good stability.In this paper,a series of heteroatom doped carbon materials were prepared by polymer-derived method and their electrocatalytic properties were investigated.The results are as follows:（1）Fe₃O₄ was used as the template,and the outer layer was coated with a polymer PZS containing three heteroatoms.After process of carbonization-etching-carbonization,N,P,S co-doped hollow carbon nanospheres materials were obtained.Due to the large specific surface area and the synergistic effect between different heteroatoms,the active sites were increased,which makes the material exhibit excellent electrocatalytic performance.For ORR test,the material showed excellent ORR catalytic activity with onset potential of 0.965 V,half-wave potential was 0.834 V and good cyclic stability.The rechargeable zinc-air battery（ZAB）assembled by the material exhibited a peak power density of 120.5 mW cm^-2 and 45h long cycle stability.（2）Conjugated microporous polymer（CoPP-FePc-CMP）was synthesized with tetramino-cobalt porphyrin（CoTAPP）and tetramino-ferrophthalocyanine（FeTAPc）as structural units,and then was combined with graphene,after calcining at high temperature,cobalt/iron/nitrogen doped graphene materials were successfully prepared.Thanks to the graphene carrier,the conductivity and circulatory stability of the material have been enhanced.Electrochemical tests showed that the composite had an onset potential of 0.957 V and a half-wave potential of 0.777 V for ORR.For OER,the potential was 1.59 V at the current density of 10 mA cm^-2.The peak power density of 53.4 mW cm^-2 was shown when the material was used as air electrode catalyst to assembled into ZAB,which showed good cycling stability.（3）A porphyrin-conjugated microporous polymer（TAPP-TFP）was synthesized using tetraaminoporphyrin（TAPP）as monomer and 1,3,5-teraldehyde-resorcinol（TFP）as bridging group.Then cobalt acetate was used as cobalt source to coordinate with TAPP-TFP,then the material was calcined to form a nitrogen-doped carbon/cobalt nanoparticle composite.Due to the synergistic effect of nitrogen-doped carbon and cobalt nanoparticle,nitrogen-doped carbon/cobalt nanoparticle composite exhibited good electrocatalytic performance.The onset potential of 0.896 V and half-wave potential of 0.744 V were shown in the ORR test,and the potential was 1.733 V when the current density was 10 mA cm^-2 in the OER test.