Oxidative properties of niobium-containing mesoporous silica catalysts

Ziółek, Maria; Sobczak, Izabela; Lewandowska, Anna E.; Nowak, Izabela; Decyk, Piotr; Renn, Monika; Jankowska, Beata

doi:10.1016/s0920-5861(01)00416-3

Cited by 101 publications

(48 citation statements)

References 34 publications

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“…In this case, an increased density of the basic sites for increased niobium content corresponded to the formation of large agglomerations of niobium phases on the outer silica shell. The existence of Nb-OH sites with a basic character rather than an acidic one has also been suggested by several authors [27,28]. The catalyst characteristics influence their performances in terms of conversion, yields towards the reaction products, and carbon efficiency (E c ) ( Table 4).…”

Section: Resultsmentioning

confidence: 73%

Direct conversion of cellulose to α-hydroxy acids (AHAs) over Nb₂O₅-SiO₂-coated magnetic nanoparticles

Candu

Anita

Podolean

et al. 2017

Green Processing and Synthesis

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A series of Nb (3 wt% or 60 wt% Nb 2 O 5 )-based magnetic nanocomposites (Nb-Si@MNP) was prepared by covering the magnetic cores with Nb 2 O 5 -SiO 2 shells using either co-precipitation or sol-gel followed by precipitation methods. These materials were exhaustively characterized through XRD, Raman spectroscopy, CO 2 -and NH 3 -TPD, DRIFT spectroscopy, and TG-DTA, after which the catalytic one-pot conversion of cellulose to valuable α-hydroxy-acids (i.e. lactic and glycolic acids) was investigated. The catalytic performances, expressed in terms of lactic and glycolic acid yields, were directly correlated to the nature of the catalytic sites which, in turn, depended on the niobia content and the preparation route.

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Section: Resultsmentioning

confidence: 73%

Direct conversion of cellulose to α-hydroxy acids (AHAs) over Nb₂O₅-SiO₂-coated magnetic nanoparticles

Candu

Anita

Podolean

et al. 2017

Green Processing and Synthesis

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“…It is known (Ziolek et al, 2001) that the low temperature (LT) peaks (below ∼1000 K) are due to the reduction of extra-framework niobium species, whereas, those at high temperatures (HT) -above ∼1000 K-characterize the reduction of niobium localized in the framework of MCM-41 samples. The reduction profiles of NbSBA-15 and NbFDU-1 samples are shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

Comparison of Adsorption Properties of Polymer-Templated Mesoporous Silicas with Incorporated Niobium

2005

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Two types of Nb-containing mesoporous materials were studied: (i) NbSBA-15 with 2D-hexagonal structure and (ii) NbFDU-1 with cage-like structure. The elucidation of the pore connectivity and the pore blockage on the basis of nitrogen and argon desorption isotherms combined with FTIR and H 2 -TPR studies is presented for niobium-containing materials. Moreover, the surface properties are studied by FTIR with NO, while the catalytic activity is examined by sulfide and cyclohexene oxidation with hydrogen peroxide.

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“…Meanwhile, Gallo et al [23] have reported that the oxidation activity of niobiumcontaining MCM-41 (Nb-MCM-41) in the epoxidation of alkene at higher temperature. Nb-MCM-41 also was applied in the oxidation of butyl sulfide and cyclohexene using H 2 O 2 at low temperature [41][42][43][44]. In that case, niobium species is located in the framework of molecularsieves.…”

Section: Performance Of Catalystsmentioning

confidence: 99%

Characterization and Catalytic Performance of Niobic Acid Dispersed over Titanium Silicalite

Prasetyoko

Ramli

Endud

et al. 2008

Advances in Materials Science and Engineering

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Niobic acid, Nb 2 O 5 ·nH 2 O, has been supported on the titanium silicalite by impregnation method. The obtained materials were characterized by X-ray diffraction, infrared, and ultra-violet-visible diffuse reflectance spectroscopy, temperature programmed reduction, pyridine adsorption, and field emission scanning electron microscopy techniques. It was demonstrated that the tetrahedral titanium species still retained after impregnation of niobic acid. The results revealed that niobium species interacted with hydroxyl groups on the surface of TS-1. The niobium species in the catalysts are predominantly polymerized niobium oxides species or bulk niobium oxide with the octahedral structure. All catalysts showed both Brønsted and Lewis acid sites. The catalysts have been tested for epoxidation of 1-octene with aqueous hydrogen peroxide. It was found that the presence of niobic acid in the catalysts enhanced the rate of the formation of epoxide at the initial reaction time. Diol as a side product was also observed due to the acidic properties of the catalysts.

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Oxidative properties of niobium-containing mesoporous silica catalysts

Cited by 101 publications

References 34 publications

Direct conversion of cellulose to α-hydroxy acids (AHAs) over Nb₂O₅-SiO₂-coated magnetic nanoparticles

Direct conversion of cellulose to α-hydroxy acids (AHAs) over Nb₂O₅-SiO₂-coated magnetic nanoparticles

Comparison of Adsorption Properties of Polymer-Templated Mesoporous Silicas with Incorporated Niobium

Characterization and Catalytic Performance of Niobic Acid Dispersed over Titanium Silicalite

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Oxidative properties of niobium-containing mesoporous silica catalysts

Cited by 101 publications

References 34 publications

Direct conversion of cellulose to α-hydroxy acids (AHAs) over Nb2O5-SiO2-coated magnetic nanoparticles

Direct conversion of cellulose to α-hydroxy acids (AHAs) over Nb2O5-SiO2-coated magnetic nanoparticles

Comparison of Adsorption Properties of Polymer-Templated Mesoporous Silicas with Incorporated Niobium

Characterization and Catalytic Performance of Niobic Acid Dispersed over Titanium Silicalite

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Direct conversion of cellulose to α-hydroxy acids (AHAs) over Nb₂O₅-SiO₂-coated magnetic nanoparticles

Direct conversion of cellulose to α-hydroxy acids (AHAs) over Nb₂O₅-SiO₂-coated magnetic nanoparticles