Design And Synthesis Of Porous Organic Polymers And Their Application In Electrocatalysis And Flexible Supercapacitor

With the quick growth of the industry in contemporary society,the need for nonrenewable energy sources and environmental harm are on the rise.Clean renewable energy,such as solar energy and wind energy,is intermittent and thus requires transformation and storage into a stable output of energy in the context of China’s"14th Five-Year Plan"for the development of renewable energy sources and the"Dual Carbon"strategic goal.At present,the research of new efficient energy conversion and energy storage theory has become a hot topic in the energy field.Electrocatalysis of alcohol oxidation and oxygen reduction is an important way of chemical energy conversion,which can promote the conversion process of chemical energy to electric energy.As an energy storage device for double layer or Faraday chemical process,the supercapacitor has become an important technology for chemical energy storage.The efficient and rational use of these green technologies is considered to be a feasible solution to effectively alleviate the energy shortage problem.However,the ambiguous active sites,poor structural design,and high production cost of electrode materials are currently the main factors limiting the development of electrocatalytic alcohol oxidation,oxygen reduction,and supercapacitor technologies.Therefore,the key to developing high-performance electrocatalytic alcohol oxidation,oxygen reduction,and supercapacitor materials is to start by regulating the structure of electrode materials and exploring inspiring design mechanisms.To address these issues,a series of materials for electrocatalytic alcohol oxidation,oxygen reduction,and supercapacitor applications have been prepared in this thesis through molecular structure design,interface engineering,and synergistic interaction of conjugated organic polymers,and the main research contents and conclusions are as follows:（1）Conjugated microporous polymers（CMPs）containing different heterocyclic rings were synthesized by using an organic heterocyclic strategy,which was used as the support of palladium-based electrocatalysts.The electronic states of the supported palladium interface were precisely regulated by S-,N-,O-and S,N-heterocyclic structures.Among them,palladium-based electrocatalysts（Pd/SNC）containing S,N thiazole heterocyclic exhibited high current densities of 1575.00 m A mg _Pd^-1 and1071.00 m A mg _Pd^-1 during methanol oxidation and ethanol oxidation,respectively.The performance of Pd/SNC was the highest in the system,exceeding that of commercial PD black electrocatalysts.DFT theoretical calculation results show that,with S,N,Pd noncovalent interaction between Pd/SNC heterojunction with moderate electron transfer（0.041|e|）,and in the volcano near the top of the figure.This work provides a promising example for the design of metal-free carbon-based support for high-efficiency alcohol oxidation by heterocyclic regulation.（2）A series of metal-free covalent organic frameworks（COFs）materials with definite heterocyclic biphenyls and fluorenyl units have been developed through Schiff base reaction using a valence bond regulation strategy.Contrary to conventional thinking,the developed method provides not only a methyl（MG）-induced molecular configuration to promote activity but also a direct opportunity to identify heteroatom-free carbon active centers.When methyl group with reversible valence bond is introduced into the original biphenyl COF,its half-wave potential reaches 0.74 V vs.RHE,which is one of the highest values of carbon-based metal-free electrocatalyst COFs as electrocatalysts for the oxygen reduction reaction.Combined with in situ Raman spectroscopy and theoretical calculation,it was obtained that the methyl group had an ortho activation effect,which confirmed that the adjacent ortho carbon（site-5）was the active center.This study provides a promising new idea for the design of high-efficiency metal-free organic catalysts by regulating valence bond strategy.（3）A flexible covalent organic framework（COFs）material was developed on the surface of alginate（SAF）fibroids as a flexible substrate by adopting the flexible covalent organic framework（COFs）strategy.SAF/COF@PPy,a new flexible supercapacitor material with great application prospects,was developed.With the advantages of high specific surface area and ordered pore structure of COFs material and the high conductivity and charge storage capacity of polypyrrole（PPy）,a high-speed electron/ion transmission channel is constructed.The material can reach the comparable capacitance of 691.25 m F cm^-2 at the scanning rate of 1.00 m A cm^-2.This work not only proposed a new flexible strategy for powder COF materials but also provided a general method for the preparation of high-performance flexible energy storage materials in the field of flexible wearable facilities.