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

Ishikawa, Satoshi; Goto, Yuichi; Kawahara, Yoshito; Inukai, Shoma; Hiyoshi, Norihito; Dummer, Nicholas F.; Murayama, Toru; Yoshida, Akihiro; Sadakane, Masahiro; Ueda, Wataru

doi:10.1021/acs.chemmater.6b05224

Cited by 27 publications

(25 citation statements)

References 66 publications

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“…These changes were observed when the electron density in the hexagonal channel was increased, suggesting that Sb in 1.2Sb-NT550 is located at the hexagonal channel of the Orth-MoVO structure. 10 Figure 7 shows Sb Kedge EXAFS and XANES spectra of 1.2Sb-NT550 and MoVSbO-hy. The results of the curve-fitting analysis of the EXAFS data of 1.2Sb-NT550 and MoVSbO-hy are also shown in Table S1.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Thermally Induced Transformation of Sb-Containing Trigonal Mo₃VO_x to Orthorhombic Mo₃VO_x and Its Effect on the Catalytic Ammoxidation of Propane

et al. 2020

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Crystalline orthorhombic Mo3VO x and trigonal Mo3VO x (Orth-MoVO and Tri-MoVO) are structurally analogous, both being constituted by pentagonal {Mo6O21}6– units and {MO6} (M = Mo, V) octahedra to form hexagonal and heptagonal channels in the crystal structure. In the present study, we found that Sb could be introduced into the Tri-MoVO structure by dispersing Tri-MoVO in 1.2 M HCl solution with dissolved Sb2O3. Sb was introduced into the Tri-MoVO structure through a redox process with constituent elements. Sb was located at the heptagonal channel of the Tri-MoVO structure in the form of infinite [O–Sb(O)−]∞ chains along the channel. Interestingly, crystal structure transformation from the Tri-MoVO structure to the Orth-MoVO structure was observed by heat treatment for Tri-MoVSbO in a crystalline structure to crystalline structure manner. After the structure transformation, Sb was located at the hexagonal channel of the Orth-MoVO structure in the form of dimers of SbO3E trigonal pyramids along the channel. We concluded that the structure transformation proceeded by the movement of the pentagonal {Mo6O21}6– unit column so as to transform the heptagonal channel of the Tri-MoVO structure to the hexagonal channel of the Orth-MoVO structure. Orth-MoVSbO formed by the above process showed substantial catalytic activity for selective ammoxidation of propane.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Thermally Induced Transformation of Sb-Containing Trigonal Mo₃VO_x to Orthorhombic Mo₃VO_x and Its Effect on the Catalytic Ammoxidation of Propane

et al. 2020

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“…Since the number of the heptagonal channels in the Tri-MoVO unit cell is three and the size of the heptagonal channel (ca. 0.40 nm) is enough to accommodate EtNH 3 + and NH 4 + , we suggest that the Tri-MoVO structure is formed with occluding EtNH 3 + and NH 4 + in the heptagonal channel micropore in a ratio of 2:1 . It is still unclear why the heptagonal channel in Tri-MoVO accommodates different types of countercations at the same time, although the locations of the different types of elements in the heptagonal channel have been reported …”

Section: Resultsmentioning

confidence: 81%

“…17 , we suggest that the Tri-MoVO structure is formed with occluding EtNH 3 + and NH 4 + in the heptagonal channel micropore in a ratio of 2:1. 22 It is still unclear why the heptagonal channel in Tri-MoVO accommodates different types of countercations at the same time, although the locations of the different types of elements in the heptagonal channel have been reported. 23 External surface areas and micropore volumes for xW-(amm) are listed in Table S2.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

True Catalytically Active Structure in Mo–V-Based Mixed Oxide Catalysts for Selective Oxidation of Acrolein

et al. 2021

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Crystalline trigonal Mo3VO x (Tri-MoVO) catalyst is constructed of {Mo6O21}6– pentagonal units and octahedral {MO6} units that form hexagonal and heptagonal channels in the crystal structure. Tri-MoVO is an extremely active catalyst for selective oxidation of acrolein (ACR) to form acrylic acid (AA), with the local structure around the heptagonal channel responsible for the catalysis. Here, promoter elements that are widely used in industrial Mo–V-based mixed oxide catalysts (W and Cu) were introduced without altering the crystal structure of Tri-MoVO. W was located at the pentagonal unit sites by replacing Mo, and Cu was located in the interstitial spaces of lattice oxygens in the corner of the heptagonal channel micropore, forming a sophisticated crystal structure involving the four constituent elements. Introduction of W improved the ACR conversion without altering AA selectivity even when the water pressure in the reaction gas was decreased, owing to the promotion of the dissociative adsorption of water. The introduction of Cu resulted in improvement of the AA selectivity from ca. 93–94% to ca. 97%. Based on the structural and elemental similarities between Tri-MoVWCuO and industrially utilized Mo–V-based mixed oxide catalysts synthesized according to the patented procedure, we concluded that Tri-MoVWCuO is the true catalytically active structure for selective oxidation of ACR.

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“…Orth-MoVO, Tri-MoVO, and ε-POM materials are very attractive because these materials are capable of substituting framework elements without altering its crystalline structure. − In addition, additional elements can be introduced into the channels and cages. These elemental diversities may allow multifunctionalization of these materials by conferring additional catalytic functions on the basis of its organized catalyst structure.…”

Section: Elemental Diversity In Crystalline Mo3vo X Oxides and ε-Keg...mentioning

confidence: 99%

“…Additional elements can be introduced into both Orth-MoVO and Tri-MoVO. Te, Sb, and Bi can be introduced into the hexagonal channel of Orth-MoVO. − The introduction of these elements significantly changed the product selectivity trend in the propane (amm)oxidation because these elements promote the allyl oxidation to form acrylic acid or acrylonitrile. − Fe or Cu can be introduced into the heptagonal channel of Tri-MoVO. , Product selectivity in allyl alcohol oxidation was clearly changed by the introduction of these elements into the heptagonal channel. Acrolein and propanal were formed as primary products with almost the same reaction rate over Tri-MoVO and Tri-MoVWO (no elements in the heptagonal channel).…”

Section: Elemental Diversity In Crystalline Mo3vo X Oxides and ε-Keg...mentioning

confidence: 99%

Unit Synthesis Approach for Creating High Dimensionally Structured Complex Metal Oxides as Catalysts for Selective Oxidations

2018

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Solid-state catalysts for selective oxidations have been prepared by simple traditional protocols including impregnation, precipitation, solid-state reaction, and so on. Although these catalyst preparation protocols are convenient to form new or improved catalysts, a huge number of practical experiments have been inevitably necessary. This situation will be even more difficult because solidstate catalysts become increasingly complex in order to introduce multifunction. It is time that catalyst researchers should devote their efforts to establish new synthetic methodology to improve the situation and ultimately create new catalysts. Here, we propose a new catalyst synthesis approach, that is, unit synthesis, to produce high dimensionally structured crystalline complex metal oxide catalysts. By applying this synthesis methodology, we have been able to synthesize several new crystalline complex metal oxides active for catalytic selective oxidations. In this Perspective, crystalline Mo 3 VO x oxides and crystalline porous material based on ε-Keggin polyoxometalates (POM) are introduced as successful examples of the unit synthesis. We found that the former shows extremely high catalytic activity for ethane oxidation to ethane and acrolein oxidation to acrylic acid with molecular oxygen and the latter for methacrolein oxidation to methacrylic acid.

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

Cited by 27 publications

References 66 publications

Thermally Induced Transformation of Sb-Containing Trigonal Mo₃VO_x to Orthorhombic Mo₃VO_x and Its Effect on the Catalytic Ammoxidation of Propane

Thermally Induced Transformation of Sb-Containing Trigonal Mo₃VO_x to Orthorhombic Mo₃VO_x and Its Effect on the Catalytic Ammoxidation of Propane

True Catalytically Active Structure in Mo–V-Based Mixed Oxide Catalysts for Selective Oxidation of Acrolein

Unit Synthesis Approach for Creating High Dimensionally Structured Complex Metal Oxides as Catalysts for Selective Oxidations

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

Cited by 27 publications

References 66 publications

Thermally Induced Transformation of Sb-Containing Trigonal Mo3VOx to Orthorhombic Mo3VOx and Its Effect on the Catalytic Ammoxidation of Propane

Thermally Induced Transformation of Sb-Containing Trigonal Mo3VOx to Orthorhombic Mo3VOx and Its Effect on the Catalytic Ammoxidation of Propane

True Catalytically Active Structure in Mo–V-Based Mixed Oxide Catalysts for Selective Oxidation of Acrolein

Unit Synthesis Approach for Creating High Dimensionally Structured Complex Metal Oxides as Catalysts for Selective Oxidations

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Product

Resources

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Thermally Induced Transformation of Sb-Containing Trigonal Mo₃VO_x to Orthorhombic Mo₃VO_x and Its Effect on the Catalytic Ammoxidation of Propane

Thermally Induced Transformation of Sb-Containing Trigonal Mo₃VO_x to Orthorhombic Mo₃VO_x and Its Effect on the Catalytic Ammoxidation of Propane