Synthesis And Characterization Of Novel Misfit-layered Compounds

Layered compound is a layered structure of the main features of the nano-scale solid materials, as a result of the reaction can provide more active sites, which make it in the nano-materials chemistry plays an important role in the high-conductivity, hydrogen storage, high-performance batteries, catalysis and other areas, has shown the great potential usefulness by chemical, electrical, aerospace, nuclear industry and other industry concerns, the international scientific community to become a research hotspot.Layered compounds known as intercalation compounds, the main material from the layered composite material and other factors have a strong anisotropy. For such compounds, the existence of a strong layer covalent bond, between the three levels of the weak force.Under certain conditions, certain substances (atoms, molecules, ions) can be overcome material layered between the three levels of force to insert reversible gap between layers will be open from the laminates and laminates to form a strong interaction, but does not damage the original layered structure, and can be inserted to control the composition and quantity.There are two subsystems with different unit cell dimensions in the misfit-layered compounds. The misfit-layered compounds are very interesting because of their unusual structures as well as their properties, and have great potential applications in the fields of the electronic materials, the optic materials, the electrical materials, the magnetic materials, the catalytic materials and so on.Niobate perovskite-type compounds and materials, because of its unique structure and physical and chemical properties, in use as ferroelectric, piezoelectric, light-emitting materials have a wide range of uses.In recent years, many niobate compounds in the photocatalytic decomposition of water, organic synthesis catalysis and environmental pollution control, etc, show a unique and superior performance, especially for the management of the environment and green non-polluting energy.Titanate inorganic products have a very excellent physical, chemical, and optical performance, with a dielectric, piezoelectric and pyroelectric properties, ferroelectricity, positive temperature coefficient effect, such as electrical properties, photocatalytic and photochromic discoloration, the photorefractive effect, such as optical properties and excellent chemical properties, its high photocatalytic, and ion-exchange intercalation reaction and the characteristics of growing concern about, in the contemporary field of science and technology have an important position.K_0.5La_0.5Ca_1.5Nb₃O₁₀ are the layered compounds with perovskite structure, K_0.81Li_0.27Ti_1.73O₄ is a typical semiconductor material. In this thesis by using K_0.5La_0.5Ca_1.5Nb₃O₁₀ and K_0.81Li_0.27Ti_1.73O₄ as precursors a series of layered insert compounds have been synthesized. The structures, compositions and properties of these compounds have been studied by XRD, IR, TG-DTA, SEM, TEM, ICP and so on.High temperature solid-phase synthesis of niobate K_0.5La_0.5Ca_1.5Nb₃O₁₀, the best conditions for synthesis of 24 hours response 1200℃; acid exchange in synthetic samples H_0.5La_0.5Ca_1.5Nb₃O₁₀ room temperature conditions for the exchange of 6mol/LHNO3 3-5 days. Discussed H_0.5La_0.5Ca_1.5Nb₃O₁₀ precursor to spin-off for the response, try them with different stripping reagents, reaction conditions are as follows: n propylamine /n H_0.5La_0.5Ca_1.5Nb₃O₁₀ = 60,120℃heat 24 hours, but because of the former's thickness body plate, high charge density, It is difficult to be completely stripped into a colloid with water treatment. Try to use the methods of synthesis will be inserted into the nickel hydroxide layer stripping samples to look forward to be inserted unmatched, but the application of hydrothermal method to divest it was difficult to sample all the spin-off into a gel, nickel hydroxide can not be inserted into this niobate interlayer species,can not synthetic the misfit-layered compound.Application of the method of hydrothermal synthesis K_0.81Li_0.27Ti_1.73O₄ as precursors to synthetic misfit-layered compound (AlTiO) --[Al_x(OH)_y·mH₂O]Ti_1.73O₄·nH₂O, synthesis conditions are as follows: 60℃water treatment within 48 hours or 120℃water treatment 24 hours.With XRD and SAED photographs TiO₂ of orthorhombic system: a1=0.3504nm , b1=0.2789nm ,c1=1.0250nm, Al(OH)3 of hexagonal: a2=b2=0.6545nm, c2= 1.0250nm.Application of the method of hydrothermal synthesis K_0.81Li_0.27Ti_1.73O₄ as precursors to synthetic misfit-layered compound (FeTiO)--[Fe_xO_y·mH₂O ]Ti_1.73O₄·nH₂O, synthesis conditions are as follows: 60℃water treatment within 48 hours or 120℃water treatment 24 hours. With XRD and SAED photographs TiO₂ of orthorhombic system: a1= 0.3451nm , b1= 0.2745nm , c1=1.0394nm , FexOy of hexagonal: a2=b2=0.6881nm,c2=1.0394nm.