Structure and Reactivity of Framework and Extraframework Iron in Fe-Silicalite as Investigated by Spectroscopic and Physicochemical Methods

Synthesis and characterization of Fe(III)-piperazine-derived complexes encapsulated in zeolite Y

“…There were matches between 30000-17000 cm -1 and at around 600 nm. 39 For the encapsulated complexes, as observed previously by Kumar and co-workers, the band between 300 and 400 nm as well as that near 500 nm can be attributed to oxo-Fe(III) ligand-metal charge transfer (LMCT), indicating the presence of small and larger Fe x O y clusters, respectively. 38 Finally, there are no significant differences between the spectra of the encapsulated complexes, suggesting that their electronic structures are very similar.…”

“…For FeY, there are no bands under 300 nm, indicating the lack of Fe(III) atoms with tetrahedral coordination. 38,39 However, a band of high intensity close to 360 nm was observed for all encapsulated complexes, including FeY. This band is characteristic of Fe(III) atoms with octahedral coordination in the presence of small oligomeric clusters of Fe x O y .…”

Direct synthesis of highly ordered Fe-SBA-15 mesoporous materials under weak acidic conditions

“…hydrocarbon oxidation, N 2 O decomposition and selective catalytic reduction of NO and N 2 O in the presence of hydrocarbon or ammonia [1][2][3]. Recently, the discovery of mesoporous materials has attracted intense interest due to their high specific surface area, uniform pore size distribution, large pore size and their highly valuable potential applications in catalysis, separation and adsorption [4,5].…”

“…In the present work, highly ordered Fe substituted SBA-15 mesoporous materials with isolated iron species are prepared via simple direct-hydrothermal methods under weak acidic conditions, and it is found that the formation of different iron species in the SBA-15 is very sensitive to the pH value of synthesis conditions. Electronic spectroscopy in the UV-vis region is a useful technique for studying the electronic state of isolated transition metal ions and aggregated transition metal oxides [1]. UV resonance Raman spectroscopy has been proven to be a powerful technique for identifying isolated transition metal atoms substituted in the framework of molecular sieves or grafted on metal oxide [32][33][34][35][36][37][38].…”

Heterogeneous advanced photo-fenton oxidation of phenolic aqueous solutions over iron-containing SBA-15 catalyst

“…The bands below 250 nm are attributed to isolated Fe 3+ in tetrahedral coordination and those between 300 and 400 nm are attributed to iron oxide nanoclusters (Fe x O y ) [11]. Both samples are free of large Fe 2 O 3 as evidenced by missing bands above 400 nm.…”