First Principle Study to Correlate Location and Activity of Ruthenium Oxide Incorporated in Alkali-Metal Hexatitanates

Ab initio total energy pseudopotential calculations were performed on ruthenium oxide incorporated alkali-metal hexatitanates to study the location and activity of ruthenium oxide. The influence of alkali metals on the activity is also monitored. The photocatalytic activity of alkali-metal hexatitanates in the presence of ruthenium oxide increases in the order Na > K > Rb. To rationalize the role of the hexatitanate structure on its activity, both ruthenium oxides incorporated and unincorporated structures were investigated. One objective is to monitor whether the ruthenium oxide incorporated in the tunnel has photocatalytic activity or not. The present results suggest that the tunnel structure in the Na-hexatitanate framework is well suited for accommodating Ru species and induces strong interaction between the active species and the host oxide. Density of state calculations were performed on both structures (with and without ruthenium oxide) to verify the activity of ruthenium oxide. It is observed that ruthenium oxide residing in the inner tunnels of the hexatitatanate structure plays an active role in photocatalysis. A novel methodology has been formulated to explore other complicated inorganic materials of interest.