Synthesis of Trigonal Mo–V–M3rd–O (M3rd = Fe, W) Catalysts by Using Structure-Directing Agent and Catalytic Performances for Selective Oxidation of Ethane

Ishikawa, Satoshi; Murayama, Toru; Kumaki, Masahiro; Tashiro, Masaya; Zhang, Zhenxin; Yoshida, Akihiro; Ueda, Wataru

doi:10.1007/s11244-016-0666-z

Cited by 15 publications

(43 citation statements)

References 38 publications

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“…Based on the above discussion, we propose that the catalytically active oxygen species in HDS-MoVO and HDS-WVO are M 6 + À OÀ V 4 + (M=Mo, W) in the oligomer units facing the heptagonal channels, because it has been reported that oligomer units are redox active during oxidation catalysis. [8,20,21,29,33] In the case of HDS-8Nb4V, we propose that trans V 5 + =O in {VO 6 } octahedra connecting the pentagonal units is the catalytically active oxygen species. This is based on the following observations: (1) B-7MR is statistically high in HDS-8Nb4V; (2) almost no UV absorption derived from IVCT was seen even after the oxidation reactions.…”

Section: Discussionmentioning

confidence: 91%

“…These textures are redox-active and thus produce active oxygen species inside the heptagonal channel. [8,20,21,29,33] Based on the similarity of the constituent structural units and elemental composition, it is reasonable to assume that the heptagonal channel texture acts as a highly catalytically active structure for ODHE and ODHP over HDS-MVO. Table 3 shows the number of heptagonal channels in the structure of HDS-MVO counted using HAADF-STEM images.…”

Section: Discussionmentioning

confidence: 99%

“…We found that the location sites of the atoms of these materials are largely dependent on the elemental properties. [21,[25][26][27][28][29] Nb can be placed in both the pentagonal unit sites and the octahedral sites connecting the pentagonal units (linkers), while V can occupy only the linker sites. On the basis of these reports, we believe that the local catalyst structure in HDS-NbVO is mainly composed of the connections between {Nb 6 O 21 } 12À pentagonal units and {VO 6 } octahedral linkers.…”

Section: Synthesis and Characterization Of Hds-nbvo Catalystsmentioning

confidence: 99%

“…The lower V/M ratio in the surface than those in the bulk are widely observed for the materials composed of the pentagonal unit. [29][30][31][32] The d values calculated from the [001] XRD peak were different depending on the constituent elements. The crystallite sizes calculated by the Scherrer equation using the [001] XRD peak were comparable in HDS-MoVO and HDS-WVO, whereas the crystallites of HDS-8Nb4V were much smaller than those of the above two catalysts.…”

Section: Catalytic Properties Of Hds-mvo (M=nb Mo W) Catalysts For Odhe and Odhpmentioning

confidence: 99%

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Nb−V Mixed Oxide with a Random Assembly of Pentagonal Units: A Catalyst for Oxidative Dehydrogenation of Ethane and Propane

et al. 2021

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High-dimensionally structured (HDS) mixed oxides of vanadium with metals (M) (e. g., Nb, Mo, and W; denoted as HDS-MVO) were constructed by {M 6 O 21 } 12À pentagonal units and {MO 6 } (M=Nb, Mo, W, or V) octahedra as linkers. The materials were synthesized using a hydrothermal method and rod-shaped solids. The random assembly of the pentagonal units and octahedra in the cross-sectional plane of the rods facilitated the formation of micropore channels along the long axis of the rods. Micropore formation was directly observed in the crosssection by HAADF-STEM. These structural features are common to HDS-NbVO, HDS-MoVO, and HDS-WVO. The catalytic activity of these three HDS-MVOs with V/Mo ratios in the range 0.35-0.39 was tested for the oxidative dehydrogenation of ethane and propane. The reaction rates per surface area for ethane oxidation and propane oxidation over the HDS-MoVO and HDS-WVO catalysts were comparable, whereas the HDS-NbVO catalyst showed an appreciable difference between the two reaction rates. Both HDS-MoVO and HDS-WVO exhibited higher selectivity for olefin formation during ethane oxidation than propane oxidation. Interestingly, the olefin selectivity over the HDS-NbVO catalyst was found to be almost independent of the alkane substrate. These catalytic features were discussed on the basis of VÀ OÀ V or VÀ OÀ Mo redox coupling and pore structure effects in HDS-MoVO and HDS-WVO and also of isolated and valence stable surface V in HDS-NbVO.

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Section: Discussionmentioning

confidence: 91%

Section: Discussionmentioning

confidence: 99%

Section: Synthesis and Characterization Of Hds-nbvo Catalystsmentioning

confidence: 99%

Section: Catalytic Properties Of Hds-mvo (M=nb Mo W) Catalysts For Odhe and Odhpmentioning

confidence: 99%

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Nb−V Mixed Oxide with a Random Assembly of Pentagonal Units: A Catalyst for Oxidative Dehydrogenation of Ethane and Propane

et al. 2021

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“…We have reported that ethane was converted to ethylene inside an empty heptagonal channel of the structure and that almost no conversion occurred over the catalyst surface in our examined temperature range. [21][22][23]53 MoVBiO has empty heptagonal channels as confirmed by N2 adsorption, and almost the same catalytic activity was therefore observed regardless of the introduction of Bi inside the structure.…”

Section: 65mentioning

confidence: 96%

Synthesis of Crystalline Microporous Mo–V–Bi Oxide for Selective (Amm)Oxidation of Light Alkanes

et al. 2017

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Bismuth (Bi) was successfully introduced into the crystalline orthorhombic Mo3VOx (MoVO) structure for the first time by using the ethylammonium cation (EtNH3 +) as a structure-directing agent in hydrothermal synthesis, and the catalytic activities of MoVOcontaining Bi (MoVBiO) for selective oxidation of ethane and ammoxidation of propane were compared with those of ternary MoVO. Bi and EtNH3 + were located in hexagonal and heptagonal channels in the MoVO structure, respectively. EtNH3 + could be removed without collapse of the crystal structure by appropriate heat treatment, leaving the heptagonal channels empty. The introduction of Bi had only a little eff ect on the catalytic activity for selective oxidation of ethane. On the other hand, the conversion of propane was significantly enhanced in propane ammoxidation. Acrylonitrile selectivity was also enhanced by the introduction of Bi, especially at high temperatures (>440 °C).

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Crystalline Microporous MoVBiO Polyoxometalates for Indirect Oxidation of Methanol to Methyl Formate: Effects of Organic Additives on Crystals Size and Catalytic Performance

Huang

Liu

et al. 2022

ChemCatChem

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Crystalline porous Mo‐V‐Bi oxides (MoVBiO) were prepared by hydrothermal synthesis approach. The effects of organic additives (methanol and tartaric acid) on the morphology and particle size of the MoVBiO crystals were investigated. The size of MoVBiO crystals was tuned in the range of 30–300 nm. It was found that methanol accelerated the formation of crystal nuclei resulting in the crystallization of small particles (30 nm), while tartaric acid inhibited the nucleation thus resulting in MoVBiO crystals with a size of 300 nm. The as‐synthesized MoVBiO samples were used in the indirect oxidation of methanol to methyl formate. The MoVBiO crystals with a size of 30 nm, synthesized with methanol, showed a high methyl nitrite conversion of 92 % and methyl formate selectivity of 94 % at 140 °C. The catalyst exhibited a relatively slow but almost constant deactivation over 50 h due to deposition of reaction species. The small MoVBiO crystals (30 nm) with more surface active sites and accessibility showed high performance in the oxidation of methanol to methyl formate in contrast to the big crystals (300 nm).

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Synthesis of Trigonal Mo–V–M3rd–O (M3rd = Fe, W) Catalysts by Using Structure-Directing Agent and Catalytic Performances for Selective Oxidation of Ethane

Cited by 15 publications

References 38 publications

Nb−V Mixed Oxide with a Random Assembly of Pentagonal Units: A Catalyst for Oxidative Dehydrogenation of Ethane and Propane

Nb−V Mixed Oxide with a Random Assembly of Pentagonal Units: A Catalyst for Oxidative Dehydrogenation of Ethane and Propane

Synthesis of Crystalline Microporous Mo–V–Bi Oxide for Selective (Amm)Oxidation of Light Alkanes

Crystalline Microporous MoVBiO Polyoxometalates for Indirect Oxidation of Methanol to Methyl Formate: Effects of Organic Additives on Crystals Size and Catalytic Performance

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