Preparation And Properties Of Porous Polymer-based Electrocatalysts

In new energy conversion and fabrication devices,electrode catalytic reaction determines the efficiency of the whole device,high-efficiency and multi-functional electrocatalyst have drawn a sea of eyes,and thus more and more researchers have begun to study low-cost and high-activity non-noble metal-based electrocatalysts.Porous polymers with high specific surface area,smooth pores and adjustable skeleton structure are expected to be used as electrocatalysts in the domain of green energy source.In this thesis,the relationship between structure and activity of porous polymer and metal coordination polymer structure and electrocatalytic manifestation was tested.The specific studies are as follows:(1)A nitrogen heterocyclic conjugated microporous polymer(aza-p)was successfully prepared by microwave method using 1,2,4,5-styrene tetramine hydrochloride and hexacyclohexanone hydrate in 1-methyl-2-pyrrolidone solvent.In order to inhibit the agglomeration of aza-p,aza-p was in situ polymerized and grown on the surface of carbon nanotubes(CNTs)to obtain aza-p/CT.Further,Co-aza-p/CT was obtained by the coordination of cobalt ion with N atom in the framework of aza-p.The results show that co-aza-p/CT with sufficient pore structure and affluent surface functional groups,and have successfully formed the expected Co-N coordination species.After co-aza-p/CT was carbonized at 800?,some cobalt atoms converted into Co3C nanoparticles which were encapsulated in graphene layers.The conclusion of electrochemical tests show that the material has outstanding ORR activity.The half wave potential is only 15 mV different from that of Pt/C,and the stability and methanol resistance are better than that of Pt/C.What' s more,its OER performance is comparable to that of commercial RuO2,and its stability is far better than RuO2.It is a kind of ORR/OER bifunctional catalysts with superior performance.When this material are used in air electrode electrocatalyst in rechargeable zinc-air battery,it shows good battery performance.At the current density of 5 mA cm-2,it can keep stable discharge for about 83 hours,and maintain a capacitance of 1000 mA h-1 g-1,which is much better than Pt/C.(2)The metal coordination porous polymer(Co-HAB)was successfully synthesized by stirring the aqueous solution of cobalt nitrate and hexahydrate and hexaaminobenzene trihydrochloride(HAB)for 2 h at room temperature.In order to inhibit the serious agglomeration of Co-HAB particles,Vulcan XC-72 carbon black were introduced in the synthesis system to make Co-HAB be loaded on it.Composites with remarkable conductivity and large specific area were obtained.On the base of the results of electrochemical measurements,it can be seen that the material has excellent catalytic properties of electrolytic water and are bifunctional electrocatalysts for the HER and OER.Although the HER electrocatalytic activity is slightly lower than that of noble metal catalysts,OER catalytic performance and stability are far superior to commercial RuO2,In the water-splitting,merely 1.54V voltage is needed for hydrogen production under the current density of 10 mA cm-2.Evidently,this composites are potential catalyst for hydrogen production.