Preparation And Properties Of Graphene Based BaTiO₃/TiO₂ Composite Photocatalytic Materials And Graphene Conductive Ink

In this paper,taking graphene as a starting point,graphene oxide and graphene were prepared using the redox method.For the application of graphene in optics,graphene based BaTiO₃/TiO₂ photocatalytic composite photocatalytic materials were synthesized on the graphene substrate.At the same time,due to the application of graphene in electrical properties conductive inks were prepared.Firstly,graphene oxides were prepared using the improved Hummers method as the research method,graphite powder as raw material,concentrated H₂SO₄ and KMnO₄ as oxidant.The best preparation conditions for graphene oxide were obtained by exploring the experimental parameters such as raw material ratio,sodium nitrate content and reaction temperature.It was characterized by infrared spectrum,Raman spectrum,X-ray diffraction and scanning electron microscope.The optimum preparation conditions were obtained when the ratio of graphite powder,potassium persulfate and calcium phosphate was 1:1:2,the content of NaNO₃ was 15%,the reaction temperature at medium temperature was 30°C,and the reaction temperature at high temperature was 90°C.Subsequently,reduced graphene oxide was prepared by using hydrazine hydrate,thiosemicarbazone and ascorbic acid as reductants,respectively and characterized by infrared spectrum,X-ray diffraction and scanning electron microscope.The optimal reduction conditions were got using ascorbic acid as the reducing agent and reacting at 120°C for 12 hours.The optimal experimental conditions for preparing modified titanium dioxide and composite photocatalytic materials by solvothermal method were discussed.UV-vis spectrum,infrared spectrum,laser Raman spectrum,thermogravimetric analysis,and scanning electron microscope were used as the main characterization methods to study the properties of the composites.When the modification temperature was 70?,the modification time was 6 h,and the amount of KH550 was 0.3%,the best modification conditions were gained.When the pH value was 10,the composites with uniform dispersion,good morphology,and strongest photocatalytic efficiency can be obtained.At this time,the photocatalytic efficiency of the composites was 60.67%.In addition,when the photocatalytic time was 5 mins,the photocatalytic efficiency of the composites was the highest,which was 64.97%.The degradation rate of methyl blue decreased with the increase of illumination time and the decrease of concentration of methyl blue solution.It was found that the photocatalytic degradation efficiency of methyl blue reached 72%after 15 minutes of illumination.Finally,conductive inks were prepared by using graphene as main conductive fillers,titanium oxide and conductive carbon black as auxiliary conductive fillers,polyvinylidene fluoride and polyvinyl alcohol as binders,respectively.The effects of graphene and titanium oxide content,conductive medium and drying temperature on the properties of conductive ink were discussed.The optimum experimental conditions for the preparation of conductive ink were obtained when the contents of graphene and titanium oxide were 4%and 1.5%,respectively,and the drying temperature was 90?.At this time,the conductivity of conductive inks was the highest,and the resistance value was 96.6?/?.