TY - JOUR
T1 - Density functional theory study of formic acid adsorption on anatase TiO2(001)
T2 - Geometries, energetics, and effects of coverage, hydration, and reconstruction
AU - Gong, Xue Qing
AU - Selloni, Annabella
AU - Vittadini, Andrea
PY - 2006/2/16
Y1 - 2006/2/16
N2 - We present density functional theory calculations and first-principles molecular dynamics simulations of formic acid adsorption on anatase TiO 2(001), the minority surface exposed by anatase TiO2 nanoparticles. A wide range of factors that may affect formic acid adsorption, such as coverage, surface hydration, and reconstruction, are considered. It is found that (i) formic acid dissociates spontaneously on unreconstructed clean TiO2(001)-1 × 1, as well as on the highly reactive ridge of the reconstructed TiO2(001)-1 × 4 surface; (ii) on both the 1 × 1 and 1 × 4 surfaces, various configurations of dissociated formic acid exist with adsorption energies of about 1.5 eV, which very weakly depend on the coverage; (iii) bidentate adsorption configurations, in which the formate moiety binds to the surface through two Ti-O bonds, are energetically more favored than monodentate ones; (iv) partial hydration of TiO2(001)-1 × 1 tends to favor the bidentate chelating configuration with respect to the bridging one but has otherwise little effect on the adsorption.energetics; and (v) physical adsorption of formic acid on fully hydrated TiO 2(001)-1 × 1 is also fairly strong. Comparison of the present results for formic acid adsorption with those for water and methanol under similar conditions provides valuable insights to the understanding of recent experimental results concerning the coadsorption of these molecules.
AB - We present density functional theory calculations and first-principles molecular dynamics simulations of formic acid adsorption on anatase TiO 2(001), the minority surface exposed by anatase TiO2 nanoparticles. A wide range of factors that may affect formic acid adsorption, such as coverage, surface hydration, and reconstruction, are considered. It is found that (i) formic acid dissociates spontaneously on unreconstructed clean TiO2(001)-1 × 1, as well as on the highly reactive ridge of the reconstructed TiO2(001)-1 × 4 surface; (ii) on both the 1 × 1 and 1 × 4 surfaces, various configurations of dissociated formic acid exist with adsorption energies of about 1.5 eV, which very weakly depend on the coverage; (iii) bidentate adsorption configurations, in which the formate moiety binds to the surface through two Ti-O bonds, are energetically more favored than monodentate ones; (iv) partial hydration of TiO2(001)-1 × 1 tends to favor the bidentate chelating configuration with respect to the bridging one but has otherwise little effect on the adsorption.energetics; and (v) physical adsorption of formic acid on fully hydrated TiO 2(001)-1 × 1 is also fairly strong. Comparison of the present results for formic acid adsorption with those for water and methanol under similar conditions provides valuable insights to the understanding of recent experimental results concerning the coadsorption of these molecules.
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U2 - 10.1021/jp056572t
DO - 10.1021/jp056572t
M3 - Article
C2 - 16471889
SN - 1520-6106
VL - 110
SP - 2804
EP - 2811
JO - Journal of Physical Chemistry B
JF - Journal of Physical Chemistry B
IS - 6
ER -