1. Determining the Location and Role of Al in Al-Modified TiO2 Nanoparticles Using Low-Temperature Heat Capacity, Electron Energy-Loss Spectroscopy, and X-ray Diffraction
- Author
-
Brian F. Woodfield, Jacob Schliesser, David B. Enfield, and Rebecca E. Olsen
- Subjects
Diffraction ,Materials science ,Dopant ,Electron energy loss spectroscopy ,Analytical chemistry ,Entropy of mixing ,Heat capacity ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Crystallography ,General Energy ,X-ray crystallography ,Physical and Theoretical Chemistry ,Spectroscopy ,Solid solution - Abstract
The location and function of dopants in metal oxide nanoparticles have been poorly characterized for many systems. We have performed heat capacity measurements, electron energy-loss spectroscopy (EELS), and X-ray diffraction (XRD) on 10 TiO2 nanoparticle samples that have different amounts of Al dopant to determine the location and function of the Al3+ cations. From the heat capacity data, lattice vacancies are observed to increase significantly with the addition of the Al dopant, suggesting Al3+ cations enter the TiO2 lattice and create vacancies due to the charge difference between Al3+ and Ti4+. The presence of gapped terms in fits of the low-temperature heat capacity data also suggests that small regions of short-range order are created within the TiO2 lattice. Entropies at T = 298.15 K were determined from the heat capacity data and show effects related to the entropy of mixing, suggesting that a solid solution of Al/TiO2 is formed. EELS data confirm that Al enters the TiO2 lattice but also indicates...
- Published
- 2015