Adsorption Configuration and Dissociative Reaction of NH3 on Anatase (101) Surface with and without Hydroxyl Groups

Abstract

This study investigates the possible adsorption configurations and dissociative reactions of NH3 on the anatase (101) surface by employing the first principles calculations. In addition, the hydroxyl group effect is also included to study how this effect influences the adsorption and the dissociative reactions. Without the presence of the hydroxyl group, the most stable adsorbate is the bidentate adsorbate Ti-N-O (Eads = 44.9 kcal/mol), and the second is the bidentate adsorbate Ti-(H)N-O (Eads = 40.8 kcal/mol). NH3 can also be adsorbed on 5c-Ti, forming H3N-Ti, which is the third most stable adsorbate (Eads = 27.5 kcal/mol). The hydroxyl group present on the surface has the effect of significantly enhancing the adsorption of the monodentate adsorbates H2N-Ti and HN-Ti. However, such a presence only slightly enhances the bidentate adsorbate Ti-N-O. In addition, the adsorption energy increases as the number of hydroxyl groups on the surface increases. The hydroxyl group also has the effect to diminish the a...