The design, synthesis and catalytic performance of vanadium-incorporated mesoporous silica with 3D mesoporous structure for propene epoxidation

Held, A.; Janiszewska, Ewa; Czerepińska, Justyna; Kowalska-Kuś, Jolanta

doi:10.1039/d0ra00349b

Cited by 8 publications

(10 citation statements)

References 42 publications

(50 reference statements)

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“…2 and 4 in Table S1) with a similar level of loading on both samples. Therefore, the study concludes that the room-temperature-synthesized V-MCM-41 material with and without a cosolvent medium is far better than the traditional method of preparation such as hydrothermal, postsynthesis, and template ion-exchange routes . All of these conventional methods require expensive autoclaves and a longer reaction time.…”

Section: Resultsmentioning

confidence: 95%

“…The electronic spectral analysis can easily distinguish these two coordination geometries with respect to their exposure sites on the materials. Extensive studies were carried out on various vanadium oxide-supported metal oxides and mesoporous materials to understand the coordination environment of vanadium oxides species. − In the reported direction, the UV study was employed for both of the catalysts under ambient conditions (hydrated state). The appearance of two strong absorption bands at ca.…”

Section: Resultsmentioning

confidence: 99%

“…On the other hand, the cause of the shift toward the high-temperature region in the case of the V-MCM-41 (AM) catalyst was mainly attributed to the progressive displacement of vanadium ions from the framework position, which led to the development of polymeric vanadium oxide species. 53 Additionally, the average surface oxidation states of vanadium were measured in both of the catalysts from the peak area of the profile (assuming a complete reduction of V 5+ species to the V 3+ ion), 58 and likely, a higher oxidation state was found to be on the V-MCM-41 (AM) catalyst.…”

Section: Characterizationmentioning

confidence: 99%

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Cosolvent and Local Environment Effects of Vanadium Incorporation on MCM-41 Catalysts for Selective Oxidation Reactions

Daniel

Gurulakshmi

Suresh

et al. 2022

ACS Appl. Nano Mater.

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Many oxidative and reductive processes have made extensive use of supported vanadium oxide catalysts. Understanding surface-active speciation and support interactions in these materials is critical to the development of heterogeneous catalysts. In this context, the vanadium incorporated on Mobil Composition of Matter No. 41 (V-MCM-41) catalysts were prepared with ethanol (AM) and without ethanol (NAM) at room temperature. The chemical and structural properties of the V-MCM-41 (AM) and V-MCM-41 (NAM) materials were studied by X-ray diffraction (XRD), N 2 physisorption, inductively coupled plasma-optical emission spectrometry (ICP-OES), diffuse reflectance UV−vis spectroscopy (DRUV−vis), temperature-programmed reduction with hydrogen (H 2 -TPR), X-ray photoelectron spectroscopy (XPS), 51 V NMR analysis, and high-resolution transmission electron microscopy (HRTEM) analysis. The TEM images showed that the V-MCM-41(AM) sample pores were arranged radially with nanosized particles. Further, the elemental analysis reports confirmed that the majority of the vanadium species were successfully loaded onto the pristine siliceous materials. However, the local environment of the vanadium and support interaction was entirely different due to the influence of ethanol in the synthesis medium. The NMR and DRUV−vis results showed that the incorporated vanadium oxide species were highly dispersed on both catalysts with an octahedral coordination environment under hydrated conditions. The detailed investigation from the XPS analysis combined with the TPR results confirmed that the fraction of the V 5+ ion on the mesoporous nanospherical V-MCM-41 (AM) catalyst was significantly larger than the bulk V-MCM-41 (NAM) catalyst. The efficiency of catalysts was tested for diphenylmethane (DPM) oxidation reaction using CO 2 -free air as an oxidant, and catalytic experiments revealed that nanospherical V-MCM-41 (AM) showed a higher catalytic activity than bulk V-MCM-41 (NAM). Differences in catalytic activity were mainly encountered by the concentration of surface-active sites, which were influenced by the radial arrangements of nanospherical particles and the diffusion capability of vanadium oxides. The Raman and NMR studies also showed that a V 5+ ion in a distorted coordination environment with a terminal VO bond is required to activate the O 2 molecule for the selective oxidation reaction. The calculated activation energies for V-MCM-41 (AM) and V-MCM-41 (NAM) were found to be 15 and 35 kJ/mol, respectively. This research paves the way to developing the nanosized MCM-41 material for a variety of shape-selective reactions and storage applications.

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Section: Resultsmentioning

confidence: 95%

Section: Resultsmentioning

confidence: 99%

Section: Characterizationmentioning

confidence: 99%

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Cosolvent and Local Environment Effects of Vanadium Incorporation on MCM-41 Catalysts for Selective Oxidation Reactions

Daniel

Gurulakshmi

Suresh

et al. 2022

ACS Appl. Nano Mater.

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“…18−21 In recent years, group V transition-metal catalysts have attracted immense attention in selective oxidation. 22,23 For example, the application of vanadium compounds in oxidation catalysis has been reported in many studies, including alkane oxidation, 24 alcohol oxidation, 25 olefin epoxidation, 26,27 lignin degradation by oxidation, etc. 28 The other two elements in group V metals, niobium and tantalum, are less investigated in oxidation catalysis.…”

Section: ■ Introductionmentioning

confidence: 99%

“…For the epoxidation of allylic alcohols or olefins with H 2 O 2 as an oxygen source, the use of catalysts including metal oxides, , transition-metal compounds, − and molecular sieves − is very common. Especially, titanium silicalite (TS-1) has been found to be a unique material that enables effective transformation of olefins into epoxides since the 1980s. − In recent years, group V transition-metal catalysts have attracted immense attention in selective oxidation. , For example, the application of vanadium compounds in oxidation catalysis has been reported in many studies, including alkane oxidation, alcohol oxidation, olefin epoxidation, , lignin degradation by oxidation, etc . The other two elements in group V metals, niobium and tantalum, are less investigated in oxidation catalysis.…”

Section: Introductionmentioning

confidence: 99%

Role of Organic Fluoride Salts in Stabilizing Niobium Oxo-Clusters Catalyzing Epoxidation

Zhou

Tang

et al. 2021

Langmuir

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We present here that easily available organic salts can stabilize/modify niobium (Nb) oxo-clusters. The as-synthesized Nb oxo-clusters have been characterized by various methods. These Nb oxo-clusters were catalytically active for the epoxidation of allylic alcohols and olefins with H2O2 as an oxidant. Notably, Nb-OC@TBAF-0.5 appeared as highly dispersed nanosized particles and showed the highest catalytic activity, which can be attributed to the following reasons on the basis of characterization. First, the strong coordination of fluorine ions with Nb sites and the steric protection with bulky organic cations led to high stabilization and dispersion of the oxo-clusters in the course of the reaction. Second, a hydrogen-bond interaction between the coordinated fluorine atom and the −OH group of allylic alcohol favored the epoxidation reaction. Third, the electron density of Nb sites decreased due to the strong electron-withdrawing ability of F– adjacent to Nb sites, thus promoting the electrophilic oxygen transfer to the CC bond.

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Introduction

Kapil

2022

Stable Supported Gold Nanoparticle Catalyst for Environmentally Responsible Propylene Epoxidation

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The design, synthesis and catalytic performance of vanadium-incorporated mesoporous silica with 3D mesoporous structure for propene epoxidation

Abstract: Novel promising vanadium catalysts based on mesoporous silica of 3D structure, namely KIT-6, SBA-12, and MCF, for the direct propene epoxidation with N2O.

Cited by 8 publications

References 42 publications

Cosolvent and Local Environment Effects of Vanadium Incorporation on MCM-41 Catalysts for Selective Oxidation Reactions

Cosolvent and Local Environment Effects of Vanadium Incorporation on MCM-41 Catalysts for Selective Oxidation Reactions

Role of Organic Fluoride Salts in Stabilizing Niobium Oxo-Clusters Catalyzing Epoxidation

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