TY - JOUR
T1 - Adsorption configurations and reactions of nitric acid on TiO 2 rutile (110) and anatase (101) surfaces
AU - Chang, Ching Yi
AU - Chen, Hsin Tsung
AU - Lin, Ming-Chang
PY - 2009/4/16
Y1 - 2009/4/16
N2 - The adsorption and reactions of the monomer and dimer of nitric acid on TiO 2 rutile (110) and anatase (101) surfaces have been studied by first-principles density functional theory with ultrasoft pseudopotential approximation. The most stable configuration of HN0 3 on the rutile surface is a molecular monodentate adsorbed on the 5-fold coordinated Ti atom with the hydrogen bonded to a neighboring surface bridging oxygen with the adsorption energy of 6.7 kcal/mol. It can dissociate its H atom to a nearest bridged oxygen with almost no barrier to produce NO 3(a) + H(a). The rotation of NO 3 requires a barrier of 12.2 kcal/mol to form the didentate configuration, Ti 5c - ON(O)-Ti 5cH-O 2c(a), which adsorbs on two 5-fold coordinated Ti atoms with the adsorption energy of 16.5 kcal/mol. In the case of the adsorption of 2HNO 3 molecules, the most stable configuration, 2(Ti 5c - ON(O)OH...O 2c(a)), has a structure similar to two single HNO 3 adsorbates on two 5-fold coordinated Ti atoms with the adsorption energy of 12.8 kcal/mol, which is about twice that of the single HN0 3 molecule. The result suggests that the interaction of the two planar HN0 3 adsorbates is negligible. The dehydration from 2(Ti 5c - ON(O)OH...O 2c(a)) forming N 2O 5(a) + H 2O(a) requires an energy barrier of 46.2 kcal/mol, indicating that the dimerization of the two HNO 3(a) is difficult. Similar adsorption phenomena appear on the anatase (101) surface. In addition, we find that the coadsorption of hydrogen plays a significant role in the adsorption energies of adsorbates, especially for the NO 3 radical, which may be employed as a linker between semiconductor quantum dots such as InN and the TiO 2 surface.
AB - The adsorption and reactions of the monomer and dimer of nitric acid on TiO 2 rutile (110) and anatase (101) surfaces have been studied by first-principles density functional theory with ultrasoft pseudopotential approximation. The most stable configuration of HN0 3 on the rutile surface is a molecular monodentate adsorbed on the 5-fold coordinated Ti atom with the hydrogen bonded to a neighboring surface bridging oxygen with the adsorption energy of 6.7 kcal/mol. It can dissociate its H atom to a nearest bridged oxygen with almost no barrier to produce NO 3(a) + H(a). The rotation of NO 3 requires a barrier of 12.2 kcal/mol to form the didentate configuration, Ti 5c - ON(O)-Ti 5cH-O 2c(a), which adsorbs on two 5-fold coordinated Ti atoms with the adsorption energy of 16.5 kcal/mol. In the case of the adsorption of 2HNO 3 molecules, the most stable configuration, 2(Ti 5c - ON(O)OH...O 2c(a)), has a structure similar to two single HNO 3 adsorbates on two 5-fold coordinated Ti atoms with the adsorption energy of 12.8 kcal/mol, which is about twice that of the single HN0 3 molecule. The result suggests that the interaction of the two planar HN0 3 adsorbates is negligible. The dehydration from 2(Ti 5c - ON(O)OH...O 2c(a)) forming N 2O 5(a) + H 2O(a) requires an energy barrier of 46.2 kcal/mol, indicating that the dimerization of the two HNO 3(a) is difficult. Similar adsorption phenomena appear on the anatase (101) surface. In addition, we find that the coadsorption of hydrogen plays a significant role in the adsorption energies of adsorbates, especially for the NO 3 radical, which may be employed as a linker between semiconductor quantum dots such as InN and the TiO 2 surface.
UR - http://www.scopus.com/inward/record.url?scp=65249174604&partnerID=8YFLogxK
U2 - 10.1021/jp810635h
DO - 10.1021/jp810635h
M3 - Article
AN - SCOPUS:65249174604
SN - 1932-7447
VL - 113
SP - 6140
EP - 6149
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
IS - 15
ER -