Experimental and theoretical studies on X-ray induced secondary electron yields in Ti and TiO2

Generation of X-ray induced secondary electrons in Ti and TiO2 was studied from both experimental and theoretical approaches, using X-ray photoelectron spectroscopy (XPS) attached to a synchrotron radiation facility and Monte Carlo simulation, respectively. The experiment revealed that the yields of secondary electrons induced by X-rays (electrons/photon) at photon energies to 4950 and 5000 eV for Ti and TiO2 are dTi(4950 eV) = 0.002 and dTi(5000 eV) = 0.014 while those for TiO2 are dTiO2 ð4950 eVÞ ¼ 0:003 and dTiO2 ð5000 eVÞ ¼ 0:018. A novel approach to obtain the escape depth of secondary electrons has been proposed and applied to Ti and TiO2. The approach agreed very well with the experimental data reported so far. The Monte Carlo simulation predicted; d Tið4950 eVÞ ¼ 0:002 and d Tið5000 eVÞ ¼ 0:011 while d TiO2 ð4950 eVÞ ¼ 0:003 and d TiO2 ð5000 eVÞ ¼ 0:015. An experimental examination on the contribution of X-ray induced secondary electrons to photocatalysis in TiO2 has also been proposed