Theoretical Calculation On Conductivity And Stability Of Ti/SnO₂+Sb₂O₅ Electrode

Ti-based oxide electrodes in electrochemical industry, such as the degradation of pollutant and electrochemical synthesis, are very promising. However, while titanium anodes were used in the case of electrolysis, the contact resistance between Ti substrate and active coating raised rapidly and induced the degradation of anodes. SnO2+Sb2O5 intermediate was employed to improve the stability and conductivity of the anodes because of TiO2 and SnO2 are the rutile structure and have the similar size in atomic radius,so they can form solid solution,but now lack of the theory of the relationship between the microstructure and properties. In recent years,Density Function Theory based on first principles calculation can predict the physical properties, material design, synthesis and evaluation , and has become an important basis for calculation of Materials Science and Core Technology. Therefore, microstructure and properties of the titanium oxide electrode materials were studied by Density Function Theory and experimental, and the research has a certain significance on the design of new Ti-based oxide electrodes material.Ti/SnO2 + Sb2O5 electrode were studied by the methods of theoretical and experimental as follows:①the formation energy and the electronic structures on Sn1-xSbxO2 solid solution were carried out at the generalized gradient approximation (GGA) level;②the cohesive energies and the electronic structure were also calculated on the Sn doped TiO2 and Ti doped SnO2 original cell;③Ti/SnO2 + Sb2O5 electrode were prepared by thermal decomposition, at the same time, the electrodes impedance spectroscopy and the accelerated life under strongly acidic conditions were tested. The results reveal that:1. The structure of SnO2 expand into a distorted rutile structure as the antimony content increases. The values of formation energies show that Sn1-xSbxO2 super cell solid solution can be generated. The conductivity reached a maximum when the doping ratio is 8.3%, and the stability reached the highest at 6.3% with the doping ratio.2. The Volume of Sn0.5Ti0.5O2 expand into a distorted rutile structure., the cohesive energies of TiO2,SnO2 and Sn0.5Ti0.5O2 are 2.52eV,2.40eV and 2.44eV, respectively, This suggests that TiO2 has the highest stability. Calculations on Density of state showed that a Sn 5s distribution of electronic states exists from the Fermi level to the lowest conduction band after Sn doped TiO2, at the same time, there is Ti 3d electronic state distribution after Ti doped SnO2., Therefore, Sn0.5Ti0.5O2 solid solution had the strongest conductivity.3. The Sn0.94Sb0.06O2 solid solution had formed according to the XRD patterns of Ti/SnO2 + Sb2O5 electrode. The EIS reveal that Rf(22?·cm2)of Ti/SnO2 + Sb2O5 electrode is lower than the R(f91?·cm2)of Ti/SnO2 electrode ; accelerated life of Ti/SnO2 + Sb2O5 electrode (28 h) is longer than Ti/SnO2 electrode(16 h).In summary, first principle was firstly introduced to conductivity and stability of Ti-based oxide electrodes in the world. The results of the theoretical agree with experimental, therefore, this research idea will provide a theoretical basis for design and study the new titanium-based oxide electrodes materials.