Preparation And Electrocatalytic Application Of Two-dimensional Carbon Graphite-acetylene Material

Graphdiyne is a new type of allotropy constructed by sp and sp² hybrid carbon according to the periodic law,as well as a two-dimensional network structure formed by benzene rings which are connected by 1,3-diacetylene bonds.Its abundant carbon bonds,unique electronic configuration,uniform holes,highlyπ-conjugated structure and excellent semiconductor properties make graphdiyne have broad application prospects in the fields of semiconductor devices,catalysis,gas separation,biomedicine and energy storage.In recent years,researchers have been committed to achieving high-efficiency applications in the fields of energy and catalysis by regulating the composition of graphdiyne materials and constructing graphdiyne to various nanostructures and morphologies.The development of element-doped graphdiyne is an important branch of graphdiyne’s research direction.The introduction of heteroatoms or functional groups can realize the diversity of graphdiyne’s structure and the adjustability of some basic physical properties such as electronic structure,bandwidth and migration rate.At present,however,it is a huge scientific challenge to prepare the graphdiyne with heteroatomic precisely doping,highly crystallinity and adjustable semiconductor properties.Based on the above background,this essay first designs and synthesizes the precursors with different structures and heteroatom doping,then selects and optimizes the methods to synthesize several kinds of graphdiyne whose heteroatoms are precisely doped and have distinct structures,and further explore the semiconducting properties of graphdiyne and their application in eletrocatalysis.1.The porphyrin group has good conjugate plane characteristics,aromaticity,spectral responsiveness and strong mental coordination characteristics.Here,we designed and synthesized a graphdiyne analogue（Por-GDY）based on porphyrin group.Use 5,10,15,20-tetraethynylporphyrin as precursor,then make it undergo a Glaser-Hay coupling reaction in copper pyridine solution to prepare high crystalline porphyrin graphdiyne.Its structural features were characterized by SEM,TEM/SAED,EDS,Raman,XPS and other test methods.Prepare porphyrin-graphdiyne（Por-GDY）on carbon cloth in situ and apply it to high efficiency electrocatalytic nitrogen reduction reaction.Por-GDY is used as a metal-free catalyst for the electrocatalytic nitrogen reduction reaction（ECNRR）,thus the in-situ carbon cloth electrode can effectively carry out the NRR reaction in the neutral electrolyte.At a potential of-0.7V（vs.RHE）,the yield of ammonia has reached to 7μg h^-1mg_cat.^-1and the Farada efficiency has reached to10%.2.Por-GDY was further treated by a simple Co²⁺solution to obtain the cobalt-loaded porphyrin graphenylene（Co Por-GDY）and characterized its morphology and structural characteristics.It is used as a dual-functional catalyst for hydrogen evolution reaction（HER）and oxygen evolution reaction（OER）,exhibiting a good catalytic effect.Under alkaline conditions,its HER overpotential is 308 m V and Tafel slope is 68m V dec^-1,while OER overpotential is 400 m V and Tafel slope is 129 m V dec^-1.3.Benzotrithiophene has good power supply capacity and plane rigidity.It was introduced into the graphdiyne system to successfully prepare high crystalline benzotrithiophene graphdiyne（BTT-GDY）.The structure and composition of BTT-GDY were characterized by SEM,TEM,Raman,XPS and so on.BTT-GDY film shows excellent semiconductor properties.With a band gap of 2.3 e V,its hole transport efficiency is 5 orders of magnitude higher than that of electron transport.BTT-GDY is a typical p-type semiconductor with two-dimensional porous structure.