Hierarchically structured Fe/ZSM-5 as catalysts for the oxidation of benzene to phenol

On the Role of Acidity in Bulk and Nanosheet [T]MFI (T=Al3+, Ga3+, Fe3+, B3+) Zeolites in the Methanol‐to‐Hydrocarbons Reaction

“…There is no significant difference in morphology between the [Al]MFI, [Ga]MFI, [Fe]MFI, and [B]MFI nanosheet samples. The bulk zeolite consists of large spherical particles with a size of several hundreds of nanometers as reported before …”

Performance of a novel microwave-based treatment technology for atrazine removal and destruction: Sorbent reusability and chemical stability, and effect of water matrices

“…On Cu/CBV-720, the 10 intensity of the absorption band at around 214 nm, corresponding to the isolated tetrahedrally or octahedrally coordinated Cu 2+ cations [27], decreased over the reuse cycles. The broad absorption band in the range of 220-300 nm on Fe/CBV-720 was attributed to the tetrahedrally or octahedrally coordinated Fe 3+ in isolated framework or extra-framework sites [28,29], while the tail in the range of 300-700 nm was ascribed to the iron dimmers [19,29]. The intensity of these two bands showed relatively small change after five use cycles, which further confirmed that Fe(III) species were much more stable than Cu 2+ species in the zeolite micropores.…”

“…In contrast, Fe 3+ cations in the micropores hydrolyzes easily (k h =10 -2. 19 ), which can cause protonation of atrazine molecules and thus enhance their sorption through the additional electrostatic interactions between the protonated atrazine molecules and the negatively charged pore wall surface [14]. That is, the sorption selectivity of CBV-720 towards atrazine is significantly enhanced with the loading of Cu 2+ and Fe(III) in its micropores due to the specific interactions with atrazine molecules brought by them ( Figure S3a).…”

“…The resulting coordination to the lattice oxygens is often unsaturated, leaving the possibility for sorption of small molecules to the metal sites [17,18]. With easy reducibility and high oxidation activity, Cu 2+ and Fe 3+ species in the zeolite micropores have been shown to accelerate the oxidation, hydroxylation, and oxydehydrogenation of organic compounds [19][20][21][22]. The catalytic activity of transition metal-exchanged zeolites is dependent on the transition metal species, their density and location, as well as the accessibility to and coordination with the sorbate molecules [23,24].…”

An acid-free route for the facile synthesis of iron-functionalized mesoporous silicas: Transformation between hollow nanospheres and cage-like mesostructures

“…220 and 250 nm, which can be assigned to isolated tetrahedrally-coordinated framework sites [54]. NS-1.5 only shows a weak shoulder at 350 nm, but tailing above 400 nm suggests the existence of a small quantity of aggregates [55,56]. This implies that not all the iron species in the initial mixture could be tetrahedrally-coordinated in the mesoporous framework when the iron content in the initial mixture is too high.…”