Construction Of Heterogeneous TiO 2 Complex And Photocatalytic Hydrogen Production

The excessive consumption of fossil energy and environmental crisis increasing, make clean and high energy of hydrogen energy become a popular alternative energy sources, and TiO₂ has always been considered the most promising catalyst photocatalytic hydrogen production, but with wider band gap, suction light narrow range and higher rate of electrons and holes of composite greatly limits the application of TiO₂.So, in order to change the TiO₂ band gap to overcome the disadvantages, realize the modification of TiO₂, to build different heterojunction structures of TiO₂, extension absorb light range, improve the activity of hydrogen production.In this paper the main research content is as follows:1By using the simple method of step solvent thermal synthesis TiO₂/titanate heterojunction composite.Choose tetrabutyl titanate as precursor, hydrazine hydrate as reducing agent.Scanning electron microscope and transmission electron microscopy are used to determine the morphology and structure characteristics of composite materials, further clarify the morphology evolution process of the sample.To explore the TiO₂/titanate composite crystal phase composition and surface state of elements, the X ray diffraction and X-ray photoelectron spectroscopy had been tested.Determined and found that the presence of the heterojunction structure to speed up the transmission so as to promote the electronic- hole for separation.After photocatalytic hydrogen production and testing, Ti O₂/titanate heterojunction show excellent hydrogen production activity, Hydrogen production rate is 230.1 μmol h- 1 per hour.2 Using one-step synthesis solvent thermal process had synthesized titanic acid sheets Then Ti O₂/graphene heterojunction composites were finally obtained through ultrasonic exfoliation and following thermal reduction process.The heterojunction material under AM1.5 illumination showed hydrogen production excellence, the highest amount of hydrogen production nearly 1 mmol, compared with pure TiO₂ increased amount of hydrogen production twice times.The introduction of graphene not only prevents the aggregation of TiO₂ to make it more stable, and greatly improve the range of visible light absorption.Though electrochemical tests illustrate, TiO₂/graphene heterostructure rapid transfer ofelectrons, and extended the photoproduction electron and hole life, increasethe activity of hydrogen production.3 Choose oxygen titanium sulfate as titanium source precursor, prepared by hydrothermal method step spindle morphology of TiO₂. After a series of high temperature sintering process, the final product is a spindleanatase and brookite mixed crystal phase of TiO₂ heterojunction composites.And along with the change of the calcination temperature, the content of the material anatase and brookite phase is also changing. Using the Rietveld analysis, when this kind of mixed crystal phase TiO₂ contains 85.5% anatase and 14.5% brookite when ultraviolet hydrogen production rate of 290.2 μmol h-1, it compared with other content and pure phase TiO₂ has higher activity of hydrogen production.