Flame Aerosol Synthesis of Vanadia–Titania Nanoparticles: Structural and Catalytic Properties in the Selective Catalytic Reduction of NO by NH3

Stark, Wendelin J.; Wegner, Karsten; Pratsinis, Sotiris E.; Baiker, Alfons

doi:10.1006/jcat.2000.3073

Cited by 166 publications

(146 citation statements)

References 41 publications

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“…For example, the emitted color of CdS quantum dots can be tuned through their band gap from 4.5 to 2.5 eV (Vossmeyer et al 1994) by the CdS particle size. Also, in selective catalytic reduction of NO with NH 3 by V 2 O 5 /TiO 2 , decreasing particle size of the TiO 2 support material reduces the formation of undesirable N 2 O byproduct (Stark et al 2001). Furthermore, Li ion batteries with small primary particles of LiFePO 4 give the best performance (Gaberscek et al 2007).…”

Section: Introductionmentioning

confidence: 99%

Air Entrainment During Flame Aerosol Synthesis of Nanoparticles

Waser

Groehn

Eggersdorfer

et al. 2014

Aerosol Science and Technology

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Section: Introductionmentioning

confidence: 99%

Air Entrainment During Flame Aerosol Synthesis of Nanoparticles

Waser

Groehn

Eggersdorfer

et al. 2014

Aerosol Science and Technology

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“…The SSA decreased from 93 to 73 m 2 g −1 when the V 2 O 5 content was increased from 1 to 20% (w/w) and dropped to 47 m 2 g −1 for a 40% (w/w) V 2 O 5 content. As a previous study of flame-made V 2 O 5 /TiO 2 catalysts has shown [9], the vanadia forms a shelllike structure onto a TiO 2 core rather than a solid solution of V atoms in the TiO 2 matrix in a flame, thereby increasing the VO x surface population density with decreasing SSA. Line broadening of the XRD patterns indicates anatase crystals of 17-37 nm, in close agreement with the calculated BET diameter ( Fig.…”

Section: Catalytic Testsmentioning

confidence: 87%

“…TEM and EELS analysis (not shown) indicated separate V 2 O 5 particles, suggesting that at higher V contents, at least a fraction of the vanadia nucleates homogeneously as individual particles, in addition to those condensing heterogeneously on the earlier-formed TiO 2 [9]. Despite the high V coverages of 16 and 27 V nm −2 , XRD patterns of the HE-FSP catalysts showed no diffraction lines attributed to crystalline VO 2 or V 2 O 5 ( Fig.…”

Section: Influence Of Preparation Variables On Structural Properties mentioning

confidence: 94%

“…Strong surface interactions between vanadia and titania result in amorphous monomeric, dimeric, and polymeric VO x species that can be formed at sub-"monolayer" (<8-10 V nm −2 ) coverage [6]. Exceeding that V coverage leads to crystalline V 2 O 5 [5] regardless of preparation method, for example, classic impregnation [7], atomic layer deposition (ALD) [8], or even vapor-fed flame synthesis [9]. Crystalline V 2 O 5 has a detrimental effect on activity and selectivity [10,11].…”

Section: Introductionmentioning

confidence: 99%

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Structure of Flame‐made Vanadia/Titania and Catalytic Behaviour in the Partial Oxidation of o‐Xylene

Schimmöller

Schulz

Ritter

et al. 2008

Chemie Ingenieur Technik

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Vanadia/titania particles with a specific surface area (SSA) up to 195 m 2 g −1 and a V 2 O 5 content up to 40% (w/w) or V coverage up to 59 V nm −2 were prepared by flame spray pyrolysis (FSP) under various conditions. The catalysts were characterized by nitrogen adsorption, X-ray diffraction, temperature-programmed reduction, and in situ Raman spectroscopy and tested for partial oxidation of o-xylene. Depending on vanadia content, monomeric, polymeric, and crystalline vanadia species were formed on TiO 2 support particles by FSP. Increasing the hightemperature particle residence time and concentration (production rate) during FSP reduced the SSA and increased the vanadia coverage of TiO 2 beyond a theoretical "monolayer" (>8-10 V nm −2 ) while retaining amorphous (monomeric and polymeric) VO x surface species. Controlling liquid precursor and dispersion gas feed rates, precursor concentration, and V 2 O 5 content allowed the tailoring of SSA and the population of the different VO x species in these vanadia/titania mixed oxides. For comparison, vanadia/titania catalysts containing 10% (w/w) V 2 O 5 with comparable SSA and V coverage were prepared by impregnation, resulting in typical amorphous (<10 V nm −2 ) and crystalline (>10 V nm −2 ) VO x species. Catalysts containing 7, 10, and 20% (w/w) V 2 O 5 were deposited directly from the flame on ceramic foams that were tested for the partial oxidation of o-xylene to phthalic anhydride. The global activity of flame-made and conventionally impregnated catalysts depended mainly on SSA and vanadia loading (number of V surface sites), whereas the amorphous or crystalline nature of the VO x species seemed to be less critical. In contrast, selectivity to phthalic anhydride was significantly affected by the nature of the VO x species; amorphous species exhibited higher selectivity for conversion <90% compared with catalysts containing crystalline V 2 O 5 .

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“…A fractional size and controlled shape of metal and functionalized metal nanoparticles, as well as properties of doped mixed oxides like Al 2 O 3 -ZrO 2 , could provide a unique possibility for highly efficient catalysis [9,10]. The catalysis provides numerous applications like alkylation and isomerization in the chemical industry [10,11], catalytic reduction of NO and NH 3 [12], or preparation of carbon nanotube-Al 2 O 3 composites with Fe catalysts [13]. Several applications of the catalytic agents together with increasing demand of high-quality structural materials call for new and controllable methods to produce nanoscale building blocks.…”

Section: Introductionmentioning

confidence: 99%

Iron Oxide Doped Alumina‐Zirconia Nanoparticle Synthesis by Liquid Flame Spray from Metal Organic Precursors

Nikkanen

Keskinen

Aromaa

et al. 2008

Journal of Nanotechnology

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The liquid flame spray (LFS) method was used to make iron oxide doped alumina-zirconia nanoparticles. Nanoparticles were generated using a turbulent, high-temperature (T max ∼3000 K) H 2 -O 2 flame. The precursors were aluminium-isopropoxide, zirconium-n-propoxide, and ferrocene in xylene solution. The solution was atomized into micron-sized droplets by high velocity H 2 flow and introduced into the flame where nanoparticles were formed. The particle morphology, size, phase, and chemical composition were determined by TEM, XRD, XPS, and N 2 -adsorption measurements. The collected particulate material consists of micron-sized aggregates with nanosized primary particles. In both doped and undoped samples, tetragonal phase of zirconia was detected in room temperature while alumina was found to be noncrystalline. In the doped powder, Fe was oxidized to Fe 2 O 3 . The primary particle size of collected sample was approximately from 6 nm to 40 nm. Doping was observed to increase the specific surface area of the powder from 39 m 2 /g to 47 m 2 /g.

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Flame Aerosol Synthesis of Vanadia–Titania Nanoparticles: Structural and Catalytic Properties in the Selective Catalytic Reduction of NO by NH3

Cited by 166 publications

References 41 publications

Air Entrainment During Flame Aerosol Synthesis of Nanoparticles

Air Entrainment During Flame Aerosol Synthesis of Nanoparticles

Structure of Flame‐made Vanadia/Titania and Catalytic Behaviour in the Partial Oxidation of o‐Xylene

Iron Oxide Doped Alumina‐Zirconia Nanoparticle Synthesis by Liquid Flame Spray from Metal Organic Precursors

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