Synthesis Of Hollow Nano-Tubular Carbon-Doped Cuprous Sulfide (C-Cu_2-xS) With Classical MOF As Precursor And The Study On Its Electrochemical And Photocatalytic Properties

Metal organic frameworks?MOFs?originated in 1990.The first successful synthesis of MOFs with stable pore structure by Yaghi group and Kitagawa group in Japan opened the door of MOFs.Since the advent of MOFs,it has been widely used in batteries,photocatalysis,electrocatalysis and other fields due to its adjustable size,large specific surface area and high porosity.In recent years,the synthesis of functional nanomaterials with MOFs as precursors has become a new research hotspot.Through physical/chemical treatment of MOFs,the synthesized materials continue the advantages of MOFs,such as porous,good framework structure,carbon-rich,good particle dispersion,etc.They show great potential in energy storage and conversion,electrocatalysis,photocatalysis and other related fields,which has attracted people's attention.At present,with the rapid development of the economy,energy and environmental problems have become more serious.Solving the energy crisis and environmental pollution is imminent and urgent,it is the current research hotspot and focus.In this paper,based on the greenhouse effect caused by excessive carbon dioxide emission,the classical organic framework material HKUST-1 was selected as the precursor to synthesize hollow tubular carbon-coated cuprous sulfide and its catalytic performance was studied to explore its application value.This article is divided into the following two aspects:1.We selected the metal organic framework HKUST-1 as the precursor,designed and synthesized a hollow tubular carbon-coated cuprous sulfide(C-Cu_2-xS)assembled from small-sized nanoparticles and nanorods,and its application in lithium-sulfur batteries was preliminarily studied.C-Cu_2-xS contains two kinds of copper sulfide crystal forms,Cu_1.81S and Cu₃₁S₁₆ and carbon is coated on the surface of the material in the form of carbon layer,which are characterized by XRD,SEM and TEM.The valence state of copper in C-Cu_2-xS was analyzed by XPS to be+1.We assembled button batteries as cathode of lithium-sulfur batteries and tested their charge-discharge cycle and impedance.It was found that the charge-discharge cycle performance and coulomb efficiency at a higher rate?0.5 C 1 C?were better than those at a lower rate?0.2 C?.At the same time,we compared the cycling performance of commercial cuprous sulfide at 1 C,and tested the impedance of C-Cu_2-x-x S.It shows that C-Cu_2-xS has certain advantages in electrochemistry,which means that it has potential application prospects in battery field.2.The C-Cu_2-xS@g-C₃N₄ three-component heterojunction was obtained by combining hollow tubular carbon coated cuprous sulfide(C-Cu_2-xS)on graphite phase carbonitride through heat treatment.The composite material achieved high-efficiency and selectivity in photocatalytic reduction of carbon dioxide under the water system.The effect of the composite on the photocatalytic efficiency was studied by changing the doping amount of C-Cu_2-xS.The stability and durability of the materials were proved by cyclic stability experiments and yield accumulation experiments.The comparative experiment demonstrated the photo-corrosion protection effect and catalytic efficiency enhancement effect of carbon coating as an electronic storage tank.The comparative experiments show that carbon coating as an electronic storage cell plays a protective role in photocatalytic corrosion and enhances the catalytic efficiency.Under visible light irradiation and water vapor conditions,C-Cu_2-xS@g-C₃N₄ can effectively reduce CO₂ to CO with a yield of 1062.6?mol.g^-1.As a common competitive reaction in photoreduction of CO2,our system effectively inhibits the formation of H2,and the selectivity to CO is higher than 97%,which is rare in the photoreduction of CO2 by g-C3N4 based materials.A series of characterization analysis shows that the enhancement of light absorption and the separation efficiency of electron-hole pairs after introduction of C-Cu_2-xS may be the main reason for the high photoreduction activity.