The adsorption and reactions of SiCl _x (x=0-4) on hydroxylated TiO ₂ anatase (101) surface: A computational study on the functionalization of titania with Cl ₂Si(O)O adsorbate

The adsorption and reactions of the SiCl _x (x=0-4) on the hydroxylated TiO ₂ anatase (101) surface have been investigated by using periodic density functional theory calculations in conjunction with the projected augmented wave (PAW) approach. The adsorption and reactions tend to occur more readily on the 'O _w' site derived from water than the 'O _s' site from TiO ₂ as revealed by the potential energy profiles and adsorption energies. The stepwise reactions of SiCl _x can be achieved by dehydrochlorination taking place by three paths: O _w-path, cross-path, and O _s-path. The O _w-path is the lowest energy path, in which Cl ₃Si-O _w(a) and Cl ₂Si-(O _w)O _w(a) are the main products formed by spontaneous reactions. The ready formation and the high stability of Cl ₂Si-(O _w)O _w(a) suggest that it can be employed as a molecular linker for Si and other semiconductor quantum dot growth on titania through its high reactivity towards SiH _x radicals and metal alkyls, respectively.