Crystalline niobia with tailored porosity as support for cobalt catalysts for the Fischer–Tropsch synthesis

Mejía, Carlos Hernández; Otter, J.H. den; Weber, Jan; Jong, Krijn P. de

doi:10.1016/j.apcata.2017.07.016

Cited by 25 publications

(20 citation statements)

References 19 publications

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“…In the case of niobic acid, intraparticle mesopores of about 5 nm were present next to the interparticle mesoporosity, as highlighted in the magnified part of Fig. 1(g) and reported before [57]. In the case of amorphous TiO2 the primary particle size was only a few nm, giving rise to micropores in addition to the mesopores, as can be observed in the magnified part of Fig.…”

Section: Materials Characterizationsupporting

confidence: 72%

Assessment of oxide nanoparticle stability in liquid phase transmission electron microscopy

2019

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Studying liquid phase nanoscale dynamic processes of oxide nanoparticles is of considerable interest to a wide variety of fields. Recently developed liquid phase transmission electron microscopy (LP-TEM) is a promising technique, but destabilization of oxides by solid-liquidelectron interactions remains an important challenge. In this work we present a methodology to assess LP-TEM oxide stability in an aqueous phase, by subjecting several oxides of technological importance to a controlled electron dose in water. We show a correlation based on the Gibbs free energy of oxide hydration that can be used to assess the stability of oxides and demonstrate the existence of several remarkably stable oxides, with no observable structural changes after one hour of electron beam irradiation in LP-TEM. Rationalizing such destabilization phenomena combined with the identification of stable oxides allows for designing LP-TEM experiments free from adverse beam effects and thus investigations of numerous relevant nanoscale processes in water.

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Section: Materials Characterizationsupporting

confidence: 72%

Assessment of oxide nanoparticle stability in liquid phase transmission electron microscopy

2019

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“…Niobium oxide presents a broad peak above 1,173 K. Nevertheless, this peak is not clear or is shifted to higher temperatures in the impregnated catalysts. This point has already been observed in other works and may be due to metal-support interaction, which may affect the reducibility of the Nb 2 O 5 (Eleutério et al, 1998;Noronha et al, 2000;Rezende et al, 2012;Hernández Mejía et al, 2017).…”

Section: Resultssupporting

confidence: 73%

“…Nb 2 O 5 is used as support in many catalytic reactions (Nowak and Ziolek, 1999). There are some studies on the use of Nb 2 O 5 as support of Fischer-Tropsch catalysts using CO (Soares et al, 1993;Mendes et al, 2006a;Den Otter and De Jong, 2014;Hernández Mejía et al, 2017), but the hydrogenation of CO 2 is considerably less studied over metal-supported Nb 2 O 5 catalysts. Nozaki et al (1987) reported the use of Rh/Nb 2 O 5 catalyst in CO 2 hydrogenation to hydrocarbons.…”

Section: Introductionmentioning

confidence: 99%

Conversion of CO2 to Light Olefins Over Iron-Based Catalysts Supported on Niobium Oxide

Silva

Mota

2019

Front. Energy Res.

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Four iron-based catalysts supported on niobium oxide (Nb 2 O 5 ) were prepared by impregnation and characterized by TPR, FRX, DRX, and textural analysis. The catalysts were tested in a fixed bed continuous flow unit to convert a mixture of CO 2 and H 2 to hydrocarbons at atmospheric pressure. All catalysts were active in the range of 623-723 K. The selectivity to hydrocarbons and light olefins increases with the use of alkali metal promoters (K or Cs). At 673 K, the Fe-Cr-K/Nb 2 O 5 showed 26% selectivity to light olefins, representing 5% yield with 20% CO 2 conversion. The niobium oxide-supported catalysts were more active and selective than the same catalyst formulation supported on SiO 2 .

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“…Similar isotherms and the evolving of the Nb 2 O 5 morphology with increasing calcination temperature has been reported elsewhere. [57] The pore size distributions of all the catalysts were calculated from the adsorption branches to avoid an artifact at ca. 4 nm caused by cavitation.…”

Section: Physisorption Measurementsmentioning

confidence: 99%

Liquid‐phase Hydrodeoxygenation of 4‐Propylphenol to Propylbenzene: Reducible Supports for Pt Catalysts

et al. 2020

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Pyrolysis and liquefaction biocrudes obtained from lignocellulose are rich in phenolic compounds that can be converted to renewable aromatics. In this study, Pt catalysts on reducible metal oxide supports (Nb2O5, TiO2), along with irreducible ZrO2 as a reference, were investigated in the liquid‐phase hydrodeoxygenation (HDO) of 4‐propylphenol (350 °C, 20 bar H2, organic solvent). The most active catalyst was Pt/Nb2O5, which led to the molar propylbenzene selectivity of 77 %, and a yield of 75 % (98 % conversion). Reducible metal oxide supports provided an increased activity and selectivity to the aromatic product compared to ZrO2, and the obtained results are among the best reported in liquid‐phase. The reusability of the spent catalysts was also studied. The spent Pt/Nb2O5 catalyst provided the lowest conversion, while the product distribution of the spent Pt/ZrO2 catalyst changed towards oxygenates. The results highlight the potential of pyrolysis or liquefaction biocrudes as a source of aromatic chemicals.

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Crystalline niobia with tailored porosity as support for cobalt catalysts for the Fischer–Tropsch synthesis

Cited by 25 publications

References 19 publications

Assessment of oxide nanoparticle stability in liquid phase transmission electron microscopy

Assessment of oxide nanoparticle stability in liquid phase transmission electron microscopy

Conversion of CO2 to Light Olefins Over Iron-Based Catalysts Supported on Niobium Oxide

Liquid‐phase Hydrodeoxygenation of 4‐Propylphenol to Propylbenzene: Reducible Supports for Pt Catalysts

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