Reactivity of Fe-binuclear complexes in over-exchanged Fe/ZSM5, studied by in situ XAFS spectroscopy Part 1: Heat treatment in He and O2

Abstract

The structure of the iron species in mildly calcined over-exchanged Fe/ZSM5, prepared by CVD of FeCl 3 , was studied during heat treatments in He or O 2 /He (50:50) by coupling in situ Fe K edge HR-XANES and EXAFS. The majority of iron appears to be present as

Methane Activation by Selective Oxidation

“…EXAFS analysis showed that in samples containing the lowest Fe concentrations, the Fe-Fe coordination number is low, and consistent with diiron species that have been suggested in previous studies [21][22][23][24][25] DFT calculations were employed to simulate model diiron species which could be compared to the EXAFS data. Of the several possible alternatives a close match was obtained for a diiron complex containing two octahedral Fe 3+ centres: [Fe2(μ2-OH)2(OH)2(H2O)2] 2+ .…”

Nanostructured Perovskites for Catalytic Combustion

“…Since the heterogeneous catalysis is a surface phenomenon, its efficiency is determined by both chemical composition and catalyst surface structure. Generally, nanostructured oxide compounds are used [2,[11][12][13] obtained by various procedures [11,12,14,15]. The nanostructure is the one which provides a large specific surface area and a superior catalyst reactivity [15].…”

“…Generally, nanostructured oxide compounds are used [2,[11][12][13] obtained by various procedures [11,12,14,15]. The nanostructure is the one which provides a large specific surface area and a superior catalyst reactivity [15]. Generally, a nanoparticle possesses a single phase crystalline core and a shell with altered crystalline structure and with several secondary phases, having a composition different from that of the core.…”

Towards advanced structural analysis of iron oxide clusters on the surface of γ-Al2O3 using EXAFS

“…Fe/ZSM-5 [1,[25][26][27][28][29], Fe/MCM-41 [30] and Fe/Al 2 O 3 [31,32], is often modelled by using bulk oxides such as α-Fe 2 O 3 neglecting the interaction of Fe with the support. As a consequence, large and strongly varying correction terms (such as the ΔE 0 ) are required to obtain a statistically reliable EXAFS fit.…”