Preparation And Properties Of Titanium- Based Porous Photothermal Conversion Materials

In the context of rapid growth of energy demand and the increasingly serious environmental problems,it is of great importance to develop cheap and efficient energy conversion and storage materials.Photothermal conversion materials are a kind of functional materials,which can transform photo energy into thermal efficiently and have been widely studied and applied in the fields of solar thermal utilization and photothermal therapy.With the development of nanotechnology,more and more materials,including metallic nanomaterials,semiconductor materials and carbon materials,have shown excellent light absorption and photothermal conversion performance,and their light absorption band and intensity can be regulated by modifying the chemical composition,microscopic size and surface morphology.The reflectivity of materials can be greatly suppressed by designing the porous surface structure,and the use of commom metals with surface plasmon resonance absorption instead of noble metals,such as gold and silver,can reduce the cost of materials.Therefore,in this thesis,the electrochemical anodization and electrodeposition have been applied to fabricate the porous photothermal conversion materials of the highly dispersed nickel nanoparticles on titanium dioxide nanotube arrays?Ni-NPs@TiO₂-NTA?,the copper nanodendrites?Cu-NDs?and black nickel coatings on titanium substrates,and the effects of morphology and composition on the optical properties have been studied.The main contents and results are as follows:?1?The honeycomb Ni-NPs@TiO₂-NTA composite porous membranes were prepared on the sueface of Ti sheets by anodization and electrodeposition.The Ni-NPs with surface plasmon resonance absorption were uniformly deposited on the walls of TiO₂-NTA.The particle size of Ni-NPs can be reduced to⁴0 nm while the absorptance can be improved after the substrate was soaked in the copper nitrate solution.The light absorptance of the Ni-NPs@TiO₂-NTA porous membrane depends greatly on the thickness and deposition time,but little on the aperture.With the thickness of 2?m and aperture of 160 nm,the light absorptance of the Ni-NPs@TiO₂-NTA can reach 96.83%.In the water heating experiment carried out with a solar simulator,the maximum water temperature of 66.5°C is obtained.?2?The Cu-NDs with high fractal and porosity were fabricated on the surface of Ti sheets by direct current electrodeposition under high current density.The optical absorptance of Cu-NDs with surface plasmon resonance absorption and optical trap effect can reach 94.89%,leading to the highest temperature of 63.9°C in the water heating experiment.?3?The non-aligned Ni-NPs@TiO₂-NTA porous membranes on the sueface of 3-D porous Ti were prepared by anodization and electrodeposition,and the black nickel coatings on the surface of 3-D porous Ti were prepared by electrodeposition.The absorptance of the NT-PT and BN-PT reaches 95.65%and 97.35%,respectively,the conversion efficiency is respectively 83.1%and 87.0%in the water evaporation experiment.