| Coal tar is one of the crude gas products produced by coal pyrolysis in the coking industry.It is a complex mixture that can be separated and processed to prepare a variety of high value-added products.Some products cannot even be replaced by petrochemicals.Therefore,research and development are high.New technologies for deep processing of coal tar with high efficiency and low pollution can not only make full use of valuable coal tar resources and reduce dependence on petroleum,but also have broad application prospects and good economic potential.In this thesis,phenanthrene in coal tar is used as raw materials,and a new synthesis process of Hexa-peri-hexabenzocoronene graphene molecules is designed and realized through a "bottom-up" strategy,which provides a way to improve the high value-added utilization of coal tar products.New way.Furthermore,the N atom-doped Hexa-peri-hexabenzocoronene graphene molecule was used as a fuel cell cathode oxygen reduction catalyst,and its ORR catalytic performance was studied.The main results are summarized as follows.(1)Using phenanthrene in coal tar as the raw material,according to the method of reverse synthesis analysis,through the "bottom-up" strategy,the " oxidation→knoevenger condensation→ Diels alder cycloaddition→oxidative cyclization dehydrogenation" was designed.The synthetic route of "dehydrogenation" successfully prepared Hexa-peri-hexabenzocoronene graphene molecules.The structure of the product was characterized by1H NMR and 13C NMR spectroscopy,HRMS,FT-IR spectroscopy and UV-vis absorption spectroscopy,and its yield was calculated..The results show that the yield of Hexa-peri-hexabenzocoronene molecules synthesized by this process can be as high as 40.4%.Compared with other reported synthesis routes,this process greatly improves the synthesis yield of Hexa-peri-hexabenzocoronene and reduces Synthesis difficulty and cost.(2)Based on the preparation process of Hexa-peri-hexabenzocoronene graphene molecules,3-iodopyridine and phenylacetylene are used to synthesize nitrogen-doped diphenylacetylene as raw materials,which are introduced into the third step "Diels-Alder cycloaddition" reaction process It reacts with cyclopentadienone in diphenyl ether solution to synthesize N-doped 1,2,3,4-tetraphenyltriphenylene,and finally obtain N-doped Hexa-peri-hexabenzocoronene graphene molecular derivative The structure of the product was characterized by hydrogen nuclear magnetic resonance spectroscopy,high-resolution mass spectrometry and elemental analysis,and the synthesis yield of N-doped Hexa-peri-hexabenzocoronene graphene molecular derivatives can reach 25.3%.(3)The N-doped Hexa-peri-hexabenzocoronene graphene molecular derivative was used as a fuel cell cathode oxygen reduction catalyst,and its oxygen reduction performance and mechanism of action were studied.The results show that the N-doped Hexa-peri-hexabenzocoronene catalyst has good oxygen reduction performance.Its oxygen reduction potential is 0.78V,limiting current density is about 5.3 mA·cm-2,half-wave potential is 0.79 V,and oxygen reduction reaction kinetics The learning process is basically close to the four-electron reaction process.Through the stability test,the N-doped Hexa-peri-hexabenzocoro-nene catalyst still maintains a current density of 91.6%after 7 hours of continuous operation.In the methanol poisoning resistance test,the N-doped Hexa-peri-hexabenzocoronene catalyst showed good resistance to methanol poisoning.Further study the surface,the oxygen reduction performance of the N-doped hexabenzocoronene catalyst is better than that of the commercial Pt/C catalyst.This is because the electronegativity of the N atom is greater than that of the C atom.N atoms enter the lattice of nano-carbon materials and use the difference in electronegativity to trigger the rearrangement of the charges of the N-doped Hexa-peri-hexabenzocoronene molecules,stimulate the electrochemical activity of the C atoms,and cause changes in the O2 adsorption mode,thereby achieving Efficient breaking of O=O bonds. |
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