Structure and morphology of hydroxylated amorphous alumina surfaces

The effect of hydroxylation on the surface structure of amorphous alumina is investigated using classical molecular dynamics simulations. It is found that the hydroxylated amorphous alumina surface is terminated by hydroxyl groups singly and doubly coordinated to aluminum. Root-mean-square roughness calculations and density profiles across the film indicate that hydroxylated surfaces are rougher than non-hydroxylated surfaces. The power spectrum identifies different vibrational stretching frequencies for the singly and doubly coordinated surface OH groups. The role of the surface OH groups in surface reactivity is discussed.