A DFT-based Analysis on H2O Molecule Adsorption and Dissociation on the Rutile TiO2 (110) and (100) Surfaces

Abstract

As part of the growing number of researches that contribute to the development of photocatalysis on TiO 2 that attests to its relevance in the future of alternative energy source, we present a comparative study on H 2 O molecular and dissociative adsorption on rutile TiO 2 (110)-(1×1) and (100)-(1×1) surfaces using density functional theory (DFT)-based analysis. Here, we show that the H 2 O molecule is more stably adsorbed molecularly on the TiO 2 (100)-(1×1) surface than on the (110)-(1×1) surface and that density of states (DOS) analysis on the system attributes this to the interacting Ti atom's higher number of states below the Fermi level for the TiO 2 (100)-(1×1) surface compared with the (110)-(1×1) surface. Furthermore, dissociation, which entails formation of OH bonds on the surface, is more favorable on the TiO 2 (100)-(1×1) than that on the TiO 2 (110)-(1×1) surfaces as indicated by a smaller activation barrier on the analyzed dissociation path and a more stable dissociated state. Theseˆndings are relevant in considering the TiO 2 (100) surface in photocatalytic reactions which is shown to have good active sites for H 2 O molecule interaction in terms of adsorption and dissociation.