PNNL

Abstract

The catalytic and photocatalytic properties of TiO2 have attracted widespread interest in a variety of applications, such as air purification, self-cleaning glass, water splitting, solar cells and wastewater treatment. In many cases the catalytic chemistry of reducible oxides is dominated by oxygen vacancy sites. For reduced rutile TiO2(110)-1×1, the bridge-bonded oxygen (BBO) vacancies (BBOV’s) are the most prevalent surface defects and, as has been shown, they can readily dissociate small molecules such as H2O, O2, and alcohols.Here we demonstrate for the first time that BBOV’s can also catalyze the transport of adsorbed species which is a key ingredient in heterogeneous catalytic processes. Specifically, we show that at elevated temperatures (= 400 K), mobile BBOV’s can assist the diffusion of alkoxy groups formed by the dissociation of alcohols at BBOV’s. This type of mechanism is likely applicable to other adsorbates bound to BBO atoms of TiO2(110).