Preparation Of Nano Titanium Nitride And Its Electrochemical Performance

Titanium nitride is an important inorganic functional material because it has many excellent properties such as strong corrosion resistance,good oxidation resistance,high chemical stability and good electrical conductivity.In this paper,the precursors of TiO₂nanotube,TiO₂ film and TiO₂ porous structure were prepared by anodic oxidation method and the titanium nitride nanotube,film and porous structure were successfully prepared through a reduction-nitridation method at 850℃using NH₃ as reductant.It was clearly seen that the chemical compositions of three nano titanium nitride materials were only Ti element and N element by EDS.The result of XRD showed that TiO₂ had been transformed into titanium nitride which mainly contained TiN phase and Ti₂N phase.The result of SEM indicated that three nano titanium nitrides still perfectly kept the microstructures of three precursors,titanium nitride nanotube and porous structure had orderly nanotube arrays and porous arrays,and the pipe diameter of nanotube and the bore diameter of porous were less than 100 nm.Four-point probe method demonstated the resistivity of three nano TiN materials was about 5.0×l0^-7?·m,which suggested that they had good electron conductivity.Potential step confirmed the real surface area of titanium nitride nanotube,porous structure and film was 1591.2 cm²,366.3 cm²,125.8 cm² respectively.The electrochemical performance of three nano titanium nitride electrodes for hydrogen evolution was studied in sulfuric acid solution by linear volt-ampere curve and Tafel curve.The result showed that three TiO₂ precursors had large surface area,but their electron conductivity was too poor,which led to high hydrogen evolution over-potential.After the nitrides were formed,it could greatly improve the ability of hydrogen evolution.Titanium nitride nanotube possessed the largest real surface area and its structure of highly ordered nanotube array was more advantageous to the rapid transport of electrons,therefore titanium nitride nanotube electrode obtained the better catalytic activity for hydrogen evolution.Using titanium nitride nanotube as middle layer,MnO₂/TiN/Ti electrode was prepared by thermal decomposition method.It`s electrochemical performance for oxygen evolution was studied in sulfuric acid solution by linear volt-ampere curve and Tafel curve.The research showed that the optimal concentration ratio for coating liquid was Mn（NO₃）₂:CH₃CH₂OH=3:5.The surface of MnO₂/Ti N/Ti electrode was smooth and the MnO₂ active layer dispersed uniformly on the surface of substrate,which showed the best properties of oxygen evolution in neutral and acidic solution.Under the low current density,it had better performance of oxygen evolution in neutral electrolyte,and under the high current density,it had better performance of oxygen evolution in acidic electrolyte.