Preparation Of Noble Metal Modified Titanium Nitride And Its Electrochemical Performance

Titanium nitride is a good electrode material for its excellent electrical conductivity,biocompatibility and corrosion resistance.Nano-structure titanium nitride,as a functional material,has attracted much attention due to its controllable preparation of the morphology,large specific surface area and pore volume.In this paper,anodic oxidation and ammonia nitride reduction methods were adopted to fabricate three kinds of titanium nitride electrodes with different morphologies,named TiN_x film electrode,nanoporous TiN_x electrode and TiN_x nanotubes electrode,respectively.After annealing at 850? in the atmosphere of ammonia,the results of XRD and EDS showed that the main phase compositions of these TiN_x electrodes are TiN and Ti₂ N and the element content of N?Atom%?in the electrodes reached 30%.Results of SEM indicated that the TiN_x film electrode has a flower like convex structure with the central part of about 1.3?m in diameter.The morphology of nanoporous TiN_x electrode is of orderly porous array structure,with about 65 nm in aperture and 54 nm in wall thickness.The surface of TiN_x nanotube electrode is of orderly nanotube arrays and the diameter of the pipes are within 100 nm.What's more,through the treatment of anodic oxidation,the roughness of the electrodes has greatly increased.The TiN_x nanotube electrode has the largest roughness,which is about 66 times higher than the polished titanium.For nanoporous TiN_x and TiN_x film electrodes,they are about 61 times and 25 times higher than the polished titanium,respectively.The as-prepared TiN_x film electrode was used as the substrate.And the electrodeposition method was adopted for the one-step modification of silver and tyrosine at the surface of TiN_x film electrode.Then,under the protection of nitrogen,Tyr-Ag/TiN_x electrode was used to explore the electro-reduction performance of hydrogen peroxide.The optimal conditions for the preparation of the electrode are as follows: in a mixed solution of 50 mM KNO3,2 mM L-Tyrosine and 1.0 mM AgNO3,the modification process was conducted by cyclic sweeping with the potential range of-0.8¹.6V,at a scan rate of 150mV/s for scanning 10 loops.Tyrosine can be used as a reducing and protective agent.It plays role in restraining the oxidation process of Ag particles.Under the synergistic effect of silver and tyrosine,the modified electrode showed a good performance for the reduction of H₂O₂.Chronoamperometry was adopted to explore the performance of Tyr-Ag/TiN_x electrode for the detection of H₂O₂,by continuous drip with H₂O₂ in phosphate buffer solution with pH 7.0.The results show that Tyr-Ag/TiN_x electrode has a good anti-interference performance with good reproducibility and stability,the detection limit of H₂O₂ was calculated to be 1.4?M.The as-prepared TiN_x electrodes were directly used for the electrochemical detection of dopamine.Chronoamperometry and differential pulse voltammetry methods were adopted for the detection of dopamine at TiN_x film electrode,nanoporous TiN_x electrode and TiN_x nanotube electrode,respectively.Results indicated that these TiN_x electrodes have electrochemical response to dopamine.The limit of detection,calculated through the results of Chronoamperometry,were 1.3?M,0.71?M,0.52?M,respectively.while using differential pulse voltammetry method,the detection limit of TiN_x film and nanoporous electrodes were 0.33?M and 0.22?M,respectively.For TiN_x nanotubes electrode,the charging current is too large,which lead to the calculated result of standard deviation in blank sample is very large.And the detection limit was calculated to be 4.3?M at TiN_x nanotubes electrode.Considering the coexistence of ascorbic acid in biological system,we also explore the limit of dopamine detection in the presence of 100?M ascorbic acid at TiN_x film electrode,nanoporous TiN_x electrode and TiN_x nanotubes electrode,which were 0.56?M,0.62?M and 4.0?M,respectively.