AVS 53rd International Symposium
    Surface Science Friday Sessions
       Session SS-FrM

Paper SS-FrM7
N and C Doping in TiO2 Using Ion Implantation for Photocatalysis Applications

Friday, November 17, 2006, 10:00 am, Room 2002

Session: Oxide Surfaces and Interfaces
Presenter: P. Nachimuthu, UNLV
Authors: P. Nachimuthu, UNLV
S. Thevuthasan, PNNL
E.K. Vestergaard, University of Washington
M.H. Engelhard, PNNL
I. Lyubinetsky, PNNL
V. Shutthanandan, PNNL
T. Tyliszczak, LBNL
D.K. Shuh, LBNL
Z. Dohnalek, PNNL
M.A. Henderson, PNNL
Correspondent: Click to Email
In semiconductor photochemistry, the redox potential of a photocatalyst is strongly influenced by its bandgap, which dictates the energy separation of the electron-hole (e@super -@/h@super +@) pairs by its band edge positions relative to electron donor/acceptor orbitals in the reactants. This in turn influences the degree of overlap between adsorbate molecular orbitals (in this case water) and the electronic states associated with the e@super -@/h@super +@ pairs. TiO@sub 2@ is one of the few candidates with promising photocatalytic properties although the optical absorption spectra of TiO@sub 2@ have poor overlap with the solar spectrum and high e@super -@/h@super +@ pair recombination rates. Solid state doping of anions causes a red-shift of the TiO@sub 2@ absorption spectrum into the visible region and visible light phtotoactivity has been observed from N-doped TiO@sub 2@. Recently, we have investigated the N and C doped in rutile TiO@sub 2@ by ion implantation. C 1s near-edge x-ray absorption fine structure (NEXAFS) shows features characteristic of Ti@sub 4@C and the intensity of these features are significantly improved following annealing at high temperatures. On the other hand, N 1s NEXAFS indicates that the features characteristic of N@sub 2@ increase with increasing annealing temperatures. XPS measurements clearly show peaks at 403 eV characteristic of N-N interaction and at 396 eV from N atom present in the substitutional/interstitial site. Nuclear reaction analysis (NRA) and XPS depth profile measurements show that N remains in the lattice following high temperature annealing. These results will be discussed along with the of ion implantation for applications in photocatalysis.