Effect of the Titania Substitution on the Electronic Structure and Transport Properties of FSS-made Fe_2O_3 Nanoparticles for Hydrogen Sensing

摘要

Substitution of Fe_2O_3 with 5-20 mole % TiO_2 by flame spray synthesis forms solid solutions of single crystal nanoparticles as small as 15.5 nm with a correspondingly high specific surface area (95 m~2/g), as measured with x-ray diffraction and transmission electron microscopy. Their electronic structure and microstructure lends the solid solution a characteristic which can be exploited for H_2 sensing, more so than pure a-Fe_2O_3. With a combination of optical spectroscopy and advanced near edge x-ray absorption fine structure (NEXAFS) spectroscopy, we are able to qualitatively probe the electronic structure and describe the mechanisms of hydrogen sensing at the molecular scale and correlate the hydrogen sensing property with charge transfer and valence band characteristics.