Fabrication Of One-dimensional Nano And Micro-nano Free-standing Electrode Materials On Titanium Substrate For Advanced Electrochemical Applications

In this thesis,high-activity self-supporting electrode materials are developed by constructing one-dimensional nanostructures on the surface of titanium metal,including nanotube array electrodes and nanofiber array electrodes.The titanium micron column array is constructed by 3D printing,and the nanotubes and nanofiber arrays were further grown to develop a micro-nano array electrode material with extremely high specific surface area.The application of these self-supporting electrode materials in sodium ion batteries,electrochemical hydrogen evolution and electrochemical sensors was studied.The main research contents include:?1?Highly ordered 1D TiO₂ NTAs directly grown on Ti current collector have been fabricated using a combination of anodization and hydrothermal method.Then prepared a carbon film coated TiO₂ nanotube array with a diameter of around 100 nm and length of 10?m.The 1D nanoarray electrode with self-supporting structure exhibits excellent sodium storage in terms of high reversible capacity(232 mA h g^-1 over 500 cycles at current density of 200 mA g^-1)and superior rate capability(68 mA h g^-1 at current density of 6.4 A g^-1).?2?The NiO nano-catalyst particles were loaded on the inner wall of the nanotube by chemical deposition,and then the polydopamine nano-film was attached to the inner wall of the nanotube by chemical polymerization.Carbonized to obtain a sandwich structure of C/NiO/TiO₂ NTAs with a diameter of around 80 nm and length of 10?m.The thickness of the nano-carbon film is about 13 nm.NiO nanoparticles with a diameter of about 20 nm are coated on the inner wall of TiO₂ nanotubes by nano-carbon film,and are evenly distributed.This sandwich-structured 1D nanoarray electrode exhibits high HER activity with an onset potential of 30 mV,an overpotential of 86 mV at 10 mA cm^-2,a Tafel slope value of 67.1 mV dec^-1 in 0.5 mol/L H₂SO₄.The catalytic performance is close to that of commercial Pt/C electrodes and is superior to most non-precious metal electrode materials.It showed excellent stability.Almost no degradation of catalytic activity is observed after 24 h test.?3?The titanium micron column arrays were fabricated by 3D printing,with diameter of 500?m and height of 5 mm for a single column.The spacing between adjacent columns is 300?m.1D TiO₂ NTAs was prepared on the surface of the micro-pillar by electrochemical anodization.Then the polydopamine nano-film was attached to the inner wall of the nanotube by chemical polymerization.After the carbonization treatment,a micro-nano structure with extremely high specific surface area is obtained,which shows good electrochemical activity and can simultaneously determine ascorbic acid and uric acid.Differential pulse voltammetry?DPV?is performed to determine UA with a linear range of 0.1-30?mol/L and sensitivity of 11.6775?A/??M·cm²?.The determination of AA shows a linear range of 100-3000?mol/L and sensitivity of 0.3186?A/??M·cm²?.?4?The titanium micron column arrays were fabricated by 3D printing,with diameter of 500?m and height of 5 mm for a single column.The spacing between adjacent columns is 300?m.TiO₂@C NFAs were grown on the surface of micro-pillars by thermochemical reaction,with diameter of⁸0 nm and length of⁵?m for a single nanofiber.Subsequent loading of molybdenum nitride nickel nanoparticles.The as-prepared electrode material exhibits excellent HER activity with an onset potential of 38 mV,an overpotential of 78mV at 10 mA cm^-2 and a Tafel slope of 86 mV dec^-1 in 0.5 mol/L H₂SO₄.The performance is superior to most non-precious metal electrode materials.