| To alleviate the increasingly serious energy crisis,the development of new energy materials is imperative.Pure carbon materials with attractive properties such as high BET area,outstanding electrical conductivity and chemical stability have been widely used as electrode material,yet its poor surface wettability as well as electrically neutral surface leads to the bad storage capacitance and electrocatalytic activity,which seriously impede the practical application.Fortunately,doping of heteroatoms into carbon matrix can overcome these deficiencies.Based on this,by utilizing condensation reaction,B-N coordination force and metal ion coordination force with tripyridine,N-containing crosslinked polymer(Ta-TAA-TPA),core-shell structured polymer nanosphere(P(St-co-DMAEMA)@BNPP)and metal-organic supramolecular polymers(Fe-Tac-Tpb)were fabricated,thus affording N-doped carbon materials(Ta-NCas),hollow carbon spheres containing B,N,P elements(BNP-HCS)and N,B and Fe co-doped carbon materials(Fe-NBC)via simple carbonization process,respectively.The composition,morphology and element content of carbon materials,which determine their supercapacitance and oxygen reduction reaction(ORR)performance,can be adjusted via the controllable construction of polymer precursors.The main research work are as follows(1)A nitrogen-rich Schiff-base polymer was synthesized via condensation reaction between 2,4,6-Tris(4-aminophenyl)-1,3,5-triazine(TAA)and terephthalaldehyde(TPA)in the presence of trifluoromethanesulfonic acid used as a catalyst.Subsequently,this precursor was carbonized at different temperatures to generate N-doped carbon materials named Ta-NCas.We focused on the effect of carbonization temperature on specific surface area,nitrogen content and wettability of Ta-NCas,which can determine on the electric double layer capacitors(EDLC)capacitance,pseudocapacitance and overall specific capacitance of the Ta-NCas.The sample(Ta-NCa850)with moderate Brunauer-Emmett-Teller area,heteroatom content and thus surface wettability displayed high capacitances as well as excellent rate capability in both acid and alkaline electrolytes.Besides,it was found that the faradaic capacitance was related to doped-heteroatoms content as well as the available utilization of heteroatoms.The EDLC was associated with the BET surface area and surface wettability.(2)Based on B-N coordination force,a artful supramolecular approach was designed to fabricate a core-shell composite with a B,N,P elements contained polymer shell(BNPP)and a poly styrene-co-N,N-dimethylaminoethyl methacrylate(P(St-co-DMAEMA)nanosphere core,thus affording hollow carbon spheres containing B,N,P elements(BNP-HCS).The shell thickness can be adjusted by altering the mass of boronic and catechol monomers and we paid attention to the effect of shell thickness on the electrochemical behavior towards supercapacitance and ORR performances.BNP-HCS-2 with moderate shell thickness exhibited highest supercapacitance in comparison with BNP-HCS-1 and BNP-HCS-3.Whereas,the ORR activity of BNP-HCS-1 was higher than that of BNP-HCS-2 and BNP-HCS-3.(3)Utilizing the coordination between terpyridinic monomer and Fe3+,Fe-Tac-Tpb and Fe-Tac-Tp metal-organic coordination polymers were fabricated using tannic acid(Tac),4'-(4-borate-phenyl)-2,2':6'.2'-tripyridine(Tpb)and 4'-(4-(bromomethyl)phenyl)-2,2':6',2"-terpyridine(TpBr)as raw materials.After a simple carbonization process,nitrogen and iron co-doped carbon materials(Fe-NC)as well as boron,nitrogen and iron co-doped carbon materials(Fe-NBC)were constructed and the effect of the boron doping on the ORR catalytic activity was investigated.Intriguingly,the content of Fe-Nx can be controllable tuned by adjusting the amount of Fe3+,and the effect of Fe-Nx content on ORR performance was studied.The results showed that the presence of iron species and B element can greatly enhanced the oxygen reduction activity of the catalyst,i.e.Fe-NBC-2 showed the best ORR activity(Eonset=0.98 V,E1/2=0.86 V,Jd=5.67 mA cm-2). |
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