Tuning of Active Sites in NiNbO Catalysts for the Direct Conversion of Ethane to Acetonitrile or Ethylene

Rubio‐Marcos, Fernando; Rojas, Estela; López‐Medina, Ricardo; Guerrero‐Pérez, M. Olga; Bañares, Miguel Á.; Fernández, J.F.

doi:10.1002/cctc.201100115

Cited by 14 publications

(15 citation statements)

References 35 publications

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“…13 In this mainly unexplored line, sepiolite seems very interesting as support for ZnO-based H 2 S sorbents. 26,27 The scope of this work is to obtain conformed solids with high surface area and porosity containing a good active phase for H 2 S sorption, ZnO, preserving the nanodispersion and the sulfidation capacity. 14 Sepiolite is a natural hydrated magnesium silicate fibrous clay with inter-and intra-particle porosity and chemical composition 19,20 Additionally, sepiolite may catalyze the Claus reaction.…”

Section: Introductionmentioning

confidence: 99%

“…Alternatively, the use of dry mixing procedures has been demonstrated as an efficient route to tailor the catalytic performance. 26,27 The scope of this work is to obtain conformed solids with high surface area and porosity containing a good active phase for H 2 S sorption, ZnO, preserving the nanodispersion and the suldation capacity. Nanostructured composite materials containing sepiolite and dispersed ZnO nanoparticles have been prepared by impregnation and dry mixing methods and conformed as monoliths by extrusion.…”

Section: Introductionmentioning

confidence: 99%

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Nanostructured ZnO/sepiolite monolithic sorbents for H₂S removal

Portela

Rubio-Marcos

Leret³

et al. 2015

J. Mater. Chem. A

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ZnO presents favorable thermodynamics, equilibrium constant and stability for H 2 S chemisorption and sepiolite has excellent sorptive and rheological properties to be employed as support. Four conformed ZnO/sepiolite composites are prepared, two by impregnation in zinc nitrate solution -one using activated carbon as dispersing and pore generating agent-and two by dry mixing of the clay with dispersed or hierarchically assembled ZnO nanoparticles. The extrudates obtained with a mixture of sepiolite and nanodispersed ZnO particles are the most active for H 2 S chemisorption in temperatureprogrammed tests performed in inert atmosphere, which can be correlated to the higher and homogeneous ZnO dispersion. ZnO sulfidation is reversible in the presence of O 2 .Thus, the activity can be regenerated, and these materials act as catalysts for H 2 S to SO 2 oxidation in air. Figure 4. TEM images (1) and proposed cartoon (2) of the thermally treated samples synthesized by impregnation method, ZnO-I (a), by impregnated carbon procedure, ZnO-ICP (b), and by dry mixing with isolated ZnO nanoparticles, ZnO-N (c), and hierarchically organized nanoparticles, ZnO-NH (d).

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Nanostructured ZnO/sepiolite monolithic sorbents for H₂S removal

Portela

Rubio-Marcos

Leret³

et al. 2015

J. Mater. Chem. A

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“…We have previously reported a solvent‐free and residue‐free preparation method to prepare hierarchical nanoscaled catalysts dispersed on microscaled particles (support) 18. 19 Thus, mixing oxides of dissimilar materials by this nanodispersion method makes it possible to obtain hierarchical nanoparticles–microparticles systems with unusual properties. After the partial reaction of the two oxides, the interfaces created reveal new and interesting properties attributed to proximity and diffusion phenomena,20, 2 which is relevant at the nanoscale range.…”

Section: Introductionmentioning

confidence: 99%

“…After the partial reaction of the two oxides, the interfaces created reveal new and interesting properties attributed to proximity and diffusion phenomena,20, 2 which is relevant at the nanoscale range. Moreover, the support and supported nanoparticles interactions can be used to tune or create magnetic, piezoelectric, and catalytic properties, depending on the temperature treatment for the nanodispersed material 19. 22, 23 Because of the small particle sizes, it is possible to characterize changes in structure spectroscopically 24.…”

Section: Introductionmentioning

confidence: 99%

Control of the Interphases Formation Degree in Co₃O₄/ZnO Catalysts

et al. 2013

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ZnO supported Co3O4 nanoparticles are highly active in the transformation of renewable materials through carbonylation of glycerol with urea. The activity of the nanoparticles is modulated by their interaction with the ZnO support, which remarkably depends on the impregnation method. One catalyst series was impregnated by conventional impregnation of a ZnO support with an aqueous solution of Co(NO3)2⋅6 (H2O), while the second set was obtained using a novel room‐temperature low‐energy dry nanodispersion method. This work focuses on the characterization and catalytic activity of both series of catalysts and describes the nature of the active sites required for the carbonylation of glycerol with urea. Raman spectroscopy and HRTEM were used to proof the nature of the interphase interaction between ZnO and Co3O4 particles in both catalyst series. Thus, it was verified such interphases are present in the catalysts prepared through the dry mixing method. Co3O4/ZnO system prepared with the dry mixing method at room temperature exhibited a catalytic behavior in the production of glycerol carbonate reaching conversion values up to 69 % in 4 h affording nearly total selectivity. There was a clear correlation between the amount of the phase and the catalytic activity. Therefore, the catalytic activity can be tuned by controlling interphase formation in Co3O4/ZnO catalysts. Upon thermal treatment, both series rearranged into inactive phases such as ZnxCo1−xCo2O4, decreasing the number of free Co3O4 related sites, which decreased the catalytic activity. Therefore, the preparation stage of the Co3O4/ZnO catalysts played an important role in the formation of this phase.

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“…19 Since that study indicated that NiO catalyst was not able to incorporate the nitrile group into ethane molecule in absence of niobium in the catalyst formulation, we investigated supported NiO/Nb 2 O 5 catalysts for ethane ammoxidation. 27,28 Two different synthesis methods for those supported catalysts were studied, a conventional impregnation, 27 and a novel dry mixing method. 28 In both cases, these studies show that NiO oxide phase is required along with the presence of a mixed Ni-Nb-O phase to obtain efficient ethane ammoxidation.…”

Section: Introductionmentioning

confidence: 99%