Density functional theory investigation of NO$_2$ and SO$_2$ adsorption on isolated and anatase-supported BaO clusters*

BaO is the most commonly used storage component in NO$_x$ storage and reduction catalysts (NSR). TiO$_2$ has recently been suggested by several authors as a promising support material, with increased sulphur tolerance when compared with traditional supports such as $\gamma$-Al$_2$O$_3$. The optimization of NSR catalysts requires knowledge of the interaction between the storage and support components. In this talk, we present a DFT investigation of the electronic and structural properties of NO$_2$ and SO$_2$ adsorption on isolated and anatase-supported (BaO)$_n$ (n=1,2,4,6,8,9) clusters. Generally, supported BaO clusters are found to display better tolerance towards sulphur poisoning compared to both bare BaO (100) surface and supported BaO overlayers.