Studies On Photocatalytic Hydrogen Evolution Using Dye Sensitized Titanate Nanotube Under Msible Light Irradiation

This paper studies the hydrothermal synthesis of titanate nanotubes(TNT) for the semiconductor, for dye sensitized to the decomposition of water to hydrogen under visible light. The research content mainly divided into the following two parts:PartⅠ: Different nickel salt modified titanate nanotubes(TNT) by simple immersion-prepare calcination method, in which the mixture of nitrogen and hydrogen as a reducing agent, and the effects of the precursors were investigated. The Ni2+ ions of the precursors can be adsorbed at both the inner and the outer surface of TNT by ion exchange, and the adsorption at the outer surface is major. More Ni2+ ions intercalate into the interlayer of TNT when nickel chloride as the precursor. During the reduction calcination process at 400 oC, the titanate transforms into anatase Ti O2, and Ni2+ ions are reduced to metal Ni nanoparticles and doped partly in Ti O2 and titanate. In the case of nickel chloride as the precursor, the phase transformation and the Ni2+ doping is much more effective than in the cases of nickel nitrate and nickel acetate as the precursors.The inner Ni2+ ions promote the phase transformation, growth of metal Ni particles and the Ni2+ doping. The formed Ni particles can be oxidized in air to form core/shell Ni@Ni O structure. The Ni2+ doping promotes formation of oxygen defects and increases the conductivity of TNT. The photocatalytic activity of Eosin Y-sensitized nickel-modified TNT for hydrogen evolution was investigated using triethanolamine(TEOA) as an electron donor under visible light irradiation(λ ≥ 420 nm). The TNT modified with nickel chloride exhibit higher activity, which can be attributed to the higher conductivity and more effective formation of Ni@Ni O structure.Part II: Titanate nanotubes was modified by nickel chloride as a precursor, further study of the effect of reduction temperature on the catalyst. Under visible light irradiation, the electron donor trethanolamine, investiagted thehydrogen evolution activity of the dye-sensitized system. The results showed that, when the reduction temperature of 400 oC showed the best activity.