Surface phase transformation of <scp>ZrO2</scp> in <scp>VOx/ZrO2</scp> catalysts for boosting propane nonoxidative dehydrogenation

Feng, Bohan; Wei, Yuechang; Xiong, Jing; Liu, Dong; Lian, Qian; Li, Yuanfeng; Han, Dong; Zhang, Zhao; Liu, Jian; Song, Weiyu; Chen, Xu

doi:10.1002/aic.18011

Cited by 4 publications

(2 citation statements)

References 46 publications

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“…Previous studies suggested that the ratio of isolated to polymerized VO X species decreases with the increase of E g values, and the values at 3.0−3.6 eV are attributed to low-polymerized VO X species. 44,49,50 Thus, isolated VO 4 species are dominant in 1V/SSZ possessing the highest E g value (3.79 eV), and with the increase of vanadium loading to 5 wt %, low-polymerized VO X species start to be formed and become prominent. Further increasing vanadium loading to 12 wt % contributes to an obvious decrease of E g values to 2.71 eV and an significant increase of CVB number (calculated based on the empirical equation CVB = −3.95E g + 14.03 established by Wachs and co-workers 51 ) to 3.33 (Table S1), potentially suggesting the formation of numerous highpolymerized VO 5 or VO 6 species for the V 2 O 5 -containing 12V/SSZ catalyst.…”

Section: Uv−vis Spectroscopymentioning

confidence: 99%

Nano-Hierarchical SSZ-13-Supported Low-Polymerized VO_X as Highly Efficient Catalysts for Propane Dehydrogenation

Sun,

Zhu,

Zhang

et al. 2024

Ind. Eng. Chem. Res.

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Supported vanadium oxide (VO X ) catalysts are promising candidates for propane dehydrogenation (PDH) due to their high catalytic activity, low cost, and environmentally benign characteristics. Herein, vanadium-based catalysts supported on hierarchical SSZ-13 zeolites with V loadings ranging from 1 to 12 wt % were prepared and evaluated in PDH reaction. The characterization results show that various kinds of VO X species are formed on the SSZ-13 zeolites, and the polymerization degree of VO X species continually increases with rising V loading. The 5V/ SSZ catalyst possessing abundant low-polymerized VO X species with a large ratio of active V 3+ and V 4+ exhibits superior catalytic activity with 19.6% propane conversion and 91.3% propylene selectivity as well as good regeneration stability. The nanohierarchical structure of SSZ-13 zeolite is also found to play an important role in enhancing PDH activity due to the suppressed coke deposition, improved mass transfer, and enhanced accessibility of propane molecules to the active sites.

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Section: Uv−vis Spectroscopymentioning

confidence: 99%

Nano-Hierarchical SSZ-13-Supported Low-Polymerized VO_X as Highly Efficient Catalysts for Propane Dehydrogenation

Sun,

Zhu,

Zhang

et al. 2024

Ind. Eng. Chem. Res.

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“…Against this background, various materials have been developed. − The most promising candidates are catalysts with supported GaO x , − VO x , − or CoO x − species. Considering the cost and environmental friendliness of zinc, ZnO x -based catalysts are of particular interest.…”

Section: Introductionmentioning

confidence: 99%

Well-Defined Supported ZnO_x Species: Synthesis, Structure, and Catalytic Performance in Nonoxidative Dehydrogenation of C₃–C₄ Alkanes

Han,

Zhao,

Kondratenko

2024

Acc. Chem. Res.

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Conspectus Zinc oxide (ZnO) is a multipurpose material and finds its applications in various fields such as rubber manufacturing, medicine, food additives, electronics, etc. It has also been intensively studied in photocatalysis due to its wide band gap and environmental compatibility. Recently, heterogeneous catalysts with supported ZnO x species have attracted more and more attention for the dehydrogenation of propane (PDH) and isobutane (iBDH) present in shale/natural gas. The olefins formed in these reactions are key building blocks of the chemical industry. These reactions are also of academic importance for understanding the fundamentals of the selective activation of C–H bonds. Differently structured ZnO x species supported on zeolites, SiO2, and Al2O3 have been reported to be active for nonoxidative dehydrogenation reactions. However, the structure–activity–selectivity relationships for these catalysts remain elusive. The main difficulty stems from the preparation of catalysts containing only one kind of well-defined ZnO x species. In this Account, we describe the studies on PDH and iBDH over differently structured ZnO x species and highlight our approaches to develop catalysts with controllable ZnO x speciation relevant to their performance. Several methods, including (i) the in situ reaction of gas-phase metallic Zn atoms with OH groups on the surface of supports, (ii) one-pot hydrothermal synthesis, and (iii) impregnation/anchoring methods, have been developed/used for the tailored preparation of supported ZnO x species. The first method allows precise control of the molecular structure of ZnO x through the nature of the defective OH groups on the supports. Using this method, a series of ZnO x species ranging from isolated, binuclear to nanosized ZnO x have been successfully generated on different SiO2-based or ZrO2-based supports as demonstrated by complementary ex/in situ characterization techniques. Based on kinetic studies and detailed characterization results, the intrinsic activity (Zn-related turnover frequency) of ZnO x was found to depend on its speciation. It increases with an increasing number of Zn atoms in a Zn m O n cluster from 1 to a few atoms (less than 10) and then decreases strongly for ZnO x nanoparticles. The latter promote the formation of undesired C1–C2 hydrocarbons and coke, resulting in lower propene selectivity in comparison with the catalysts containing only ZnO x species ranging from isolated to subnanometer Zn m O n clusters. In addition, the strategy for improving the thermal stability of ZnO x species and the consequences of mass-transport limitations for DH reactions were also elucidated. The results obtained allowed us to establish the fundamentals for the targeted preparation of well-structured ZnO x species and the relationships between their structures and the DH performance. This knowledge may inspire further studies in the field of C–H bond activation and other reactions, in which ZnOx species act as catalytically active sites or promoters, such ...

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Anatase‐reinforced PtZn@Silicalite‐1 structured catalysts boosting propane dehydrogenation

Xia,

Zhang,

Hou

et al. 2024

AIChE Journal

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Structured catalysts exhibit the advantages of high diffusion efficiency and low heat transfer resistance, which have attracted increasing attention to non‐adiabatic gas–solid process. However, the metal‐supported coating catalysts face the problems of weaker bond strength and severe sintering, especially under the conditions of large flow rate and high temperature. Herein, metal@Silicalite‐1 structured catalysts with high adhesion and thermal stability were successfully prepared by hydroxylating the substrate with anatase. Rich surface Ti‐OH significantly strengthened the adhesion stability of the zeolite coating. In propane dehydrogenation reaction, the optimized PtZn@S‐1‐15Ti showed a high specific activity of 49.6 molC3H6·molPt−1·s−1 with propylene selectivity above 99% at 600°C. The introduction of anatase accelerated the aggregation of silicon sources and induced nucleation with growth content of zeolite increased by 3.6 times. It breaks the inherent contradiction between high loading amount and strong binding ability of coated catalysts, which broadens the avenues for industrial applications.

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Surface phase transformation of ZrO₂ in VO_x/ZrO₂ catalysts for boosting propane nonoxidative dehydrogenation

Cited by 4 publications

References 46 publications

Nano-Hierarchical SSZ-13-Supported Low-Polymerized VO_X as Highly Efficient Catalysts for Propane Dehydrogenation

Nano-Hierarchical SSZ-13-Supported Low-Polymerized VO_X as Highly Efficient Catalysts for Propane Dehydrogenation

Well-Defined Supported ZnO_x Species: Synthesis, Structure, and Catalytic Performance in Nonoxidative Dehydrogenation of C₃–C₄ Alkanes

Anatase‐reinforced PtZn@Silicalite‐1 structured catalysts boosting propane dehydrogenation

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Surface phase transformation of ZrO2 in VOx/ZrO2 catalysts for boosting propane nonoxidative dehydrogenation

Cited by 4 publications

References 46 publications

Nano-Hierarchical SSZ-13-Supported Low-Polymerized VOX as Highly Efficient Catalysts for Propane Dehydrogenation

Nano-Hierarchical SSZ-13-Supported Low-Polymerized VOX as Highly Efficient Catalysts for Propane Dehydrogenation

Well-Defined Supported ZnOx Species: Synthesis, Structure, and Catalytic Performance in Nonoxidative Dehydrogenation of C3–C4 Alkanes

Anatase‐reinforced PtZn@Silicalite‐1 structured catalysts boosting propane dehydrogenation

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Surface phase transformation of ZrO₂ in VO_x/ZrO₂ catalysts for boosting propane nonoxidative dehydrogenation

Nano-Hierarchical SSZ-13-Supported Low-Polymerized VO_X as Highly Efficient Catalysts for Propane Dehydrogenation

Nano-Hierarchical SSZ-13-Supported Low-Polymerized VO_X as Highly Efficient Catalysts for Propane Dehydrogenation

Well-Defined Supported ZnO_x Species: Synthesis, Structure, and Catalytic Performance in Nonoxidative Dehydrogenation of C₃–C₄ Alkanes