291945 Non-Metal Doping of TiO2 to Increase Photocatalytic Degradation of Pollutants

Monday, October 29, 2012
Hall B (Convention Center )
Jay Y. Westcott IV1, Christopher L. Muhich1 and Charles B. Musgrave2, (1)Chemical and Biological Engineering, University of Colorado at Boulder, Boulder, CO, (2)Department of Chemical and Biological Engineering, University of Colorado, Boulder, Bouler, CO

Anatase TiO2 is commonly used as a photochemical catalyst for the degradation of pollutants in applications ranging from water treatment, self-cleaning walls and windows, to anti-bacterial surface coatings.  Platinum (Pt) is often deposited on TiO2 to increase its photocatalytic activity by providing excess electron density, which increases O2 adsorption on TiO2, and hence O2 reduction, the rate limiting step in TiO2 based pollutant degradation.  However, the rarity and expense of Pt limit it’s utilization as an additive to TiO2 for photochemical processes.  Therefore, using periodic boundary condition density functional theory (DFT), we investigated the possibility of using non-metal (Nitrogen, Carbon, and Boron) in place of Pt as the source of the excess electron density required for O2 adsorption.  Boron was the superior dopant: providing the most excess electron density at the required energy for O2 adsorption to the doped TiO2 surface followed by C and then N.  This is seen in the: O2 adsorption energies, electron transfer to the absorbed O2, O2 bond lengths, and density of states plots for the different dopants.  For example in the cases of N, C, and B the most stable O2 adsorption energies were: 0.16 eV, 1.11 eV, 1.54 eV and had electron transfers of 0.52 electrons, 0.52 electrons, and 0.94 electrons respectively.

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