A DFT-based Analysis on H_2O Molecule Adsorption and Dissociation on the Rutile TiO_2 (110) and (100) Surfaces

摘要

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_2O 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_2O 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. These findings are relevant in considering the TiO_2 (100) surface in photocatalytic reactions which is shown to have good active sites for H_2O molecule interaction in terms of adsorption and dissociation.