TY - JOUR
T1 - Investigation of local structure effect and X-ray absorption characteristics (EXAFS) of Fe (Ti) K-edge on photocatalyst properties of SrTi (1-x)Fe xO (3-δ)
AU - Ghaffari, M.
AU - Liu, T.
AU - Huang, H.
AU - Tan, O. K.
AU - Shannon, M.
PY - 2012/10/15
Y1 - 2012/10/15
N2 - In this study, the STF x photocatalyst powder was synthesized with a high temperature solid state reaction. The microstructures and surface of samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The electronic properties and local structure of the perovskite STF x (0 ≤ x ≤ 1) systems were probed by extended X-ray absorption fine structure (EXAFS) spectroscopy. The XPS results revealed that with increasing iron doping, the amount of Fe 3+ and Fe 4+ increased significantly. The X-ray absorption data are discussed in detail with respect to the Fe (Ti) K-edge. The substitution of iron by titanium increased the Ti (Fe)-O first shell disorder factors that can be explained by increasing the oxygen vacancies. Oxygen vacancies or defects act as electron traps, which could capture the photo induced electrons and thus could effectively inhibit the recombination of the photo induced electrons and holes. Moreover due to the substitution of Ti with Fe, lattice shrinkage was observed and the largest derivation from the Gaussian distribution in STF x was from those samples with x = 0.6 and x = 0.8. The substitution of iron by titanium increased the iron valence state, hence the formation of the Jahn-Teller Fe 4+ ion. With increasing iron dopant the [Ti(Fe)-O] ave decreased and bond length of [Ti-O] and the consequent [Ti-O-Ti] increased and this phenomenon affected the photocatalyst and photo degradation properties of material and also decreased its efficiency.
AB - In this study, the STF x photocatalyst powder was synthesized with a high temperature solid state reaction. The microstructures and surface of samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The electronic properties and local structure of the perovskite STF x (0 ≤ x ≤ 1) systems were probed by extended X-ray absorption fine structure (EXAFS) spectroscopy. The XPS results revealed that with increasing iron doping, the amount of Fe 3+ and Fe 4+ increased significantly. The X-ray absorption data are discussed in detail with respect to the Fe (Ti) K-edge. The substitution of iron by titanium increased the Ti (Fe)-O first shell disorder factors that can be explained by increasing the oxygen vacancies. Oxygen vacancies or defects act as electron traps, which could capture the photo induced electrons and thus could effectively inhibit the recombination of the photo induced electrons and holes. Moreover due to the substitution of Ti with Fe, lattice shrinkage was observed and the largest derivation from the Gaussian distribution in STF x was from those samples with x = 0.6 and x = 0.8. The substitution of iron by titanium increased the iron valence state, hence the formation of the Jahn-Teller Fe 4+ ion. With increasing iron dopant the [Ti(Fe)-O] ave decreased and bond length of [Ti-O] and the consequent [Ti-O-Ti] increased and this phenomenon affected the photocatalyst and photo degradation properties of material and also decreased its efficiency.
KW - Catalyst
KW - Oxygen vacancies
KW - SrTi Fe O
KW - XAFS
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U2 - 10.1016/j.matchemphys.2012.06.037
DO - 10.1016/j.matchemphys.2012.06.037
M3 - Article
AN - SCOPUS:84867403467
SN - 0254-0584
VL - 136
SP - 347
EP - 357
JO - Materials Chemistry and Physics
JF - Materials Chemistry and Physics
IS - 2-3
ER -