MOSCOW, June 3. /TASS/ Using numerical modeling, the joint research team from Russia, USA, and China has discovered new surface features of rutile TiO2, which is a promising photocatalyst.The calculations have been performed in the Moscow Institute of Physics and Technology (MIPT) on the supercomputer Rurik. The results have been published.
"Our work has broadened the current knowledge on the structure of rutile crystals, we have emphasized the role of kinetics and analyzed the surface structures," said Qinggao Wang, the corresponding author of paper, the research assistant from the Laboratory of Computational Design at MIPT.
By means of rutile, the water can be split with the release of ecologically benign fuel, the hydrogen. Moreover, the titanium dioxide (TiO2) and light can be used to purify and disinfect water and air, and to split dangerous organic contaminations. The authors believe that the performed investigations not only enrich the knowledge on the atomic structure of rutile surface but also provide better understanding of photocatalytic properties.
The activity of rutile as a catalyst is defined by the mutual arrangement of oxygen and titanium atoms on the crystal surface. For the reconstruction of TiO2 crystals, a number of models have been proposed previously but not all of them are consistent with the experimental data and have a reasonable structure.
In this work, using special software and computer modeling based on the fundamental laws of quantum mechanics, the scientists evaluated the dependence of surface energy on composition. In addition, the researchers have calculated the surface tension – the force acting on atoms on the surface.
The physicists also have used the data on the metastable forms of rutile crystals surfaces which could persist for a very long lime in the absence of external disturbances. Based on the calculations results, the scientists have concluded that some surface types predicted earlier are metastable. The structural peculiarities have been elaborated.