Facet-dependent catalytic activity of anatase TiO2 for the selective catalytic reduction of NO with NH3: A dispersion-corrected density functional theory study

Abstract

Recently, the facet-dependent catalytic activity of anatase TiO2 for the selective catalytic reduction of NO with NH3 (NH3-SCR) has been observed experimentally. In this study, the NH3-SCR of NO on the TiO2 (001) and (101) surfaces was systematically investigated using dispersion-corrected density functional theory. We propose that the surface-assisted mechanism is predominant on the (001) surface, which involves the oxygen active sites playing a crucial role in facilitating the reaction. The NH3 dissociation step reveals the largest activation energy barrier (Ea) of 61 kJ/mol on the (001) surface, whereas the NH2NO decomposition step has the largest barrier, Ea ≈ 156 kJ/mol, on the (101) surface. The results obtained by calculation are consistent with the experimental results, which have shown that a TiO2 nanosheet with a dominant (001) facet shows superior catalytic performance in NH3-SCR of NO compared to TiO2 nanoparticles with dominant (101) facet.