Induced infrared spectral enhancement in doped TiO2

PHYS 485

Tsang-Hsiu Wang, wang010@bama.ua.edu1, Raluca Craciun, craci002@bama.ua.edu1, David A. Dixon, dadixon@bama.ua.edu1, and James L. Gole, jim.gole@physics.gatech.edu2. (1) Department of Chemistry, The University of Alabama, Shelby Hall, Box 870336, Tuscaloosa, AL 35487-0336, (2) Schools of Physics and Mechanical Engineering, Georgia Institute of Technology, 837 State Street, NW, Atlanta, GA 30332-0430
Cobalt(II) and Nickel(II) ion seeding of a nitrogen doped titanium oxynitride, TiO2-xNx, leads to a significant enhancement of the infrared spectrum associated with adventitious water and minor contaminants resulting from the oxynitride synthesis of a porous TiO2 nanocolloid sample. There is substantial enhancement of the infrared intensity in the region of 2000 to 3000 cm-1. Density functional theory calculations at the B3LYP/DZVP2 level show that there is substantial infrared intensity enhancement due to partial proton transfer from protonated amines to oxygens on the TiO2 surface. The position of the band and the intensity are related to the proton affinity of the amine with larger proton affinities leading to less proton transfer, higher frequencies, and lower intensity enhancements. The intensity enhancement also has contributions from modification of the anatase ionic crystal dipole moment and the incorporation of a spinel-like structure into the TiO2 lattice.
 

PHYS Poster Session - Nanostructured Materials and Nanophotonics
7:30 PM-10:00 PM, Wednesday, April 9, 2008 Morial Convention Center -- Hall A, Poster

Division of Physical Chemistry

The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008