Structure, reactivity, photoactivity and stability of Ti-O based materials: a theoretical comparison

Ti-O based materials have attracted great attention recently for their potential applications in clean energy generation and environment remediation. To screen Ti-O based materials for specific applications, the atomic-level understanding of the subtle discrepancy of their properties is of paramount importance. In this regard, the density functional theory computations have been performed to systematically compare the physicochemical properties of three selected Ti-O based materials: anatase titanium dioxides, sodium trititanates and sodium hexatitanates. Due to their structure discrepancy, sodium trititanates show the highest chemical reactivity. However, titanium dioxides are found to be the most photoactive materials. The reactivity and photoactivity of sodium hexatitanates fall between those of titanium dioxide and sodium trititanates. In the meantime, our energetic analysis also confirms that the thermal stabilities of Ti-O based materials are strongly dependent on the acid-base conditions. Titanium dioxides are preferred under acidic conditions, while titanates are more stable in basic solutions.