Effect of alkali metal added to supported La catalysts on the catalytic activity in the gas-phase catalytic oxidation of benzyl alcohol

Furukawa, Masaya; Nishikawa, Yoko; Nishiyama, Satoru; Tsuruya, Shigeru

doi:10.1016/j.molcata.2003.10.009

Cited by 16 publications

(6 citation statements)

References 10 publications

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“…In addition, the mass-specific activity (24.7 mmol·g cat –1 ·h –1 ) of the 1.0 mol % VO x -CeO 2 is 5-fold higher than that of 5.0 mol % K-Cu-TiO 2 , close to the 2.5% Au/TiO 2 in the liquid-phase solvent-free BA-to-BAD oxidation . To the best of our knowledge, it is the highest TOF and reaction rate reported so far for transition metal heterogeneous catalysts for BA-to-BAD oxidation at such low temperatures in the gas phase. − Once the vanadium content was further increased to 5.0 mol %, the mass-specific activity decreases sharply with the temperature increase, which is opposite to the performances of other VO x -CeO 2 catalysts with low vanadium content (Figure a), in accordance with the change of the polymeric state of VO x (dimers/monomers) to trimers as monitored by Raman spectroscopy.…”

Section: Resultsmentioning

confidence: 76%

Origin of the High Activity of Mesoporous CeO₂ Supported Monomeric VO_x for Low-Temperature Gas-Phase Selective Oxidative Dehydrogenation of Benzyl Alcohol: Role As an Electronic “Hole”

Liu

Zou

et al. 2014

J. Phys. Chem. C

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Herein, we report a newly developed mesoporous VO x -CeO 2 catalyst with dominant monomeric VO x species, which can promote the gas-phase ODH reaction of benzyl alcohol-tobenzaldehyde (BA-to-BAD) by molecular oxygen at a surprisingly low temperature range of 203−243°C, with a high mass-specific activity of ∼25 mmol·g cat −1 ·h −1 and TOF of 1367 h −1 . To the best of our knowledge, it appears to be the most effective transition metal oxides catalyst for the BA-to-BAD reaction in the gas phase. Experimental measurements and density functional theory (DFT) calculations suggest that the activities of VO x -CeO 2 catalysts strongly depend on the polymeric states of surface VO x , with monomeric VO x giving much better performance than bigger VO x clusters. It is important to highlight that a specific monomeric VO 3 species, only occurring under the reaction conditions, is identified for the first time to have the key influence on BA oxidation. Moreover, it has been found that the origin for the unique activity of such monomeric VO x -CeO 2 can be attributed to its electronic "hole" structure.

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Section: Resultsmentioning

confidence: 76%

Origin of the High Activity of Mesoporous CeO₂ Supported Monomeric VO_x for Low-Temperature Gas-Phase Selective Oxidative Dehydrogenation of Benzyl Alcohol: Role As an Electronic “Hole”

Liu

Zou

et al. 2014

J. Phys. Chem. C

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“…Therefore, the oxygen species of silver oxides are the strongest basic species among other oxides, which exhibit more negative charge . Typically, the acidic sites often promote alcohol dehydration, and the basic sites favor alcohol dehydrogenation . Thus, in this case, possibly, the facets of silver in Ag 2 O act as ideal multifunctional facets that facilitate the regeneration of oxidative, strong basic oxygen species and weak acidic sites quickly for the catalytic cycles, such as molecular oxygen activation, alcohol chemical adsorption, and the subsequent dehydrogenation.…”

Section: Resultsmentioning

confidence: 99%

Green, Solvent-Free Mechanochemical Synthesis of Nano Ag₂O/MnO₂/N-Doped Graphene Nanocomposites: An Efficient Catalyst for Additive-Base-Free Aerial Oxidation of Various Kinds of Alcohols

Hatshan,

Khan,

Assal

et al. 2024

ACS Omega

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Herein, we report a solvent-less, straightforward, and facile mechanochemical technique to synthesize nanocomposites of Ag 2 O nanoparticles-doped MnO 2 , which is further codoped with nitrogen-doped graphene (N-DG) [i.e., (X %)N-DG/MnO 2 −(1% Ag 2 O)] using physical milling of separately prepared N-DG and Ag 2 O NPs−MnO 2 annealed at 400 °C over an eco-friendly ball-mill process. To assess the efficiency in terms of catalytic performance of the nanocomposites, selective oxidation of benzyl alcohol (BlOH) to benzaldehyde (BlCHO) is selected as a substrate model with an ecofriendly oxidizing agent (O 2 molecule) and without any requirements for the addition of any harmful additives or bases. Various nanocomposites were prepared by varying the amount of N-DG in the composite, and the results obtained highlighted the function of N-DG in the catalyst system when they are compared with the catalyst MnO 2 −(1% Ag 2 O) [i.e., undoped catalyst] and MnO 2 −(1% Ag 2 O) codoped with different graphene dopants such as GRO and H-RG for alcohol oxidation transformation. The effects of various catalytic factors are systematically evaluated to optimize reaction conditions. The N-DG/MnO 2 −(1% Ag 2 O) catalyst exhibits premium specific activity (16.0 mmol/h/g) with 100% BlOH conversion and <99.9% BlCHO selectivity within a very short interval. The mechanochemically prepared N-DG-based nanocomposite displayed higher catalytic efficacy than that of the MnO 2 −(1% Ag 2 O) catalyst without the graphene dopant, which is N-DG in this study. A wide array of aromatic, heterocyclic, allylic, primary, secondary, and aliphatic alcohols have been selectively converted to respective ketones and aldehydes with full convertibility without further oxidation to acids over N-DG/MnO 2 −(1% Ag 2 O). Interestingly, it is also found that the N-DG/MnO 2 −(1% Ag 2 O) can be efficiently reused up to six times without a noteworthy decline in its effectiveness. The prepared nanocomposites were characterized using various analytical, microscopic, and spectroscopic techniques such as X-ray diffraction, thermogravimetric analysis, Fourier-transform infrared spectroscopy, Raman, field emission scanning electron microscopy, and Brunauer−Emmett−Teller.

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“…A strong peak at around 2.7 Å, which is attributed to Ag−Ag bonding, , was observed for Ag foil [Figure a]. The EXAFS of the Ag 2 O powder exhibited a peak at around 1.7 Å attributed to Ag−O bonding [Figure b]. , A weak broad peak at around 3.3 Å will be attributed to the Ag−O−Ag bonding. , Two peaks at around 1.7 Å and around 2.7 Å were observed for the Ag(1)/SiO 2 catalyst without added Ca [Figure c]. The EXAFS of the Ca−Ag(1)/SiO 2 catalysts exhibits a peak at around 1.7 Å, but the peak at around 2.7 Å markedly declined, and this tendency became more notable with the increase in the Ca/Ag atomic ratio (Figure d,e).…”

Section: Resultsmentioning

confidence: 99%

“…The EXAFS of the Ag 2 O powder exhibited a peak at around 1.7 Å attributed to Ag-O bonding [Figure 6b]. 22,24 A weak broad peak at around 3.3 Å will be attributed to the Ag-O-Ag bonding. 26,28 Two peaks at around 1.7 Å and around 2.7 Å were observed for the Ag(1)/ SiO 2 catalyst without added Ca [Figure 6c].…”

Section: Behavior Of Partial Oxidation Of Benzyl Alcohol In the Absen...mentioning

confidence: 99%

“…The oxidation of alcohols including methanol was studied over supported Ag catalysts in a flow reactor and using temperature-programmed oxidation (TPO) method . Patent literature reported that unsaturated alcohols could be converted to the corresponding aldehydes over supported Cu, Ag, and Au catalysts and alloys thereof. , We have reported the gas-phase oxidation of benzyl alcohol using O 2 as an oxidant over alkali metal added Cu, − Ce, , La, and Co − catalysts supported on inorganic oxides. The added alkali metals were found to play an important role in selectively promoting the partial oxidation of benzyl alcohol to benzaldehyde.…”

Section: Introductionmentioning

confidence: 99%

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Promoting Effect and Role of Alkaline Earth Metal Added to Supported Ag Catalysts in the Gas-Phase Catalytic Oxidation of Benzyl Alcohol

Sawayama

Shibahara

Ichihashi

et al. 2006

Ind. Eng. Chem. Res.

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The effect and the role of alkaline earth metals added to Ag/SiO 2 catalyst were studied in the gas-phase catalytic oxidation of benzyl alcohol. The main oxidation product was benzaldehyde, together with only small amounts of CO 2 , benzene, and toluene, depending on the reaction conditions. The influence of the method regarding how to add the alkaline earth metal to the supported Ag catalyst, and the amount of the added alkaline earth metal on the partial oxidation activity, was investigated, along with the analyses of these alkaline earth metal added Ag/SiO 2 catalysts by diffuse reflectance (DR) spectroscopy, XRD, thermal gravimetricdifferential thermal analyses (TG-DTA), and extended X-ray absorption fine structure (EXAFS). The addition of alkaline earth metals such as Ca, Sr, and Ba to the Ag/SiO 2 catalyst by a coimpregnation method significantly promoted the catalytic activity of the partial oxidation of benzyl alcohol. The surface oxygen species on the supported Ag played an important role in the partial oxidation of benzyl alcohol on the basis of the results of the transient response experiment and the O 2 adsorption on the prereduced Ag/SiO 2 catalysts with and without alkaline earth metal. The alkaline earth metal added to the Ag/SiO 2 catalyst was suggested to inhibit the formation of carbonaceous material, make the metallic Ag disperse, and facilitate the adsorption of oxygen on the Ag surface to form an oxygenated Ag surface, which was thought to be responsible for the partial oxidation of benzyl alcohol.

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Effect of alkali metal added to supported La catalysts on the catalytic activity in the gas-phase catalytic oxidation of benzyl alcohol

Cited by 16 publications

References 10 publications

Origin of the High Activity of Mesoporous CeO₂ Supported Monomeric VO_x for Low-Temperature Gas-Phase Selective Oxidative Dehydrogenation of Benzyl Alcohol: Role As an Electronic “Hole”

Origin of the High Activity of Mesoporous CeO₂ Supported Monomeric VO_x for Low-Temperature Gas-Phase Selective Oxidative Dehydrogenation of Benzyl Alcohol: Role As an Electronic “Hole”

Green, Solvent-Free Mechanochemical Synthesis of Nano Ag₂O/MnO₂/N-Doped Graphene Nanocomposites: An Efficient Catalyst for Additive-Base-Free Aerial Oxidation of Various Kinds of Alcohols

Promoting Effect and Role of Alkaline Earth Metal Added to Supported Ag Catalysts in the Gas-Phase Catalytic Oxidation of Benzyl Alcohol

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Effect of alkali metal added to supported La catalysts on the catalytic activity in the gas-phase catalytic oxidation of benzyl alcohol

Cited by 16 publications

References 10 publications

Origin of the High Activity of Mesoporous CeO2 Supported Monomeric VOx for Low-Temperature Gas-Phase Selective Oxidative Dehydrogenation of Benzyl Alcohol: Role As an Electronic “Hole”

Origin of the High Activity of Mesoporous CeO2 Supported Monomeric VOx for Low-Temperature Gas-Phase Selective Oxidative Dehydrogenation of Benzyl Alcohol: Role As an Electronic “Hole”

Green, Solvent-Free Mechanochemical Synthesis of Nano Ag2O/MnO2/N-Doped Graphene Nanocomposites: An Efficient Catalyst for Additive-Base-Free Aerial Oxidation of Various Kinds of Alcohols

Promoting Effect and Role of Alkaline Earth Metal Added to Supported Ag Catalysts in the Gas-Phase Catalytic Oxidation of Benzyl Alcohol

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Origin of the High Activity of Mesoporous CeO₂ Supported Monomeric VO_x for Low-Temperature Gas-Phase Selective Oxidative Dehydrogenation of Benzyl Alcohol: Role As an Electronic “Hole”

Origin of the High Activity of Mesoporous CeO₂ Supported Monomeric VO_x for Low-Temperature Gas-Phase Selective Oxidative Dehydrogenation of Benzyl Alcohol: Role As an Electronic “Hole”

Green, Solvent-Free Mechanochemical Synthesis of Nano Ag₂O/MnO₂/N-Doped Graphene Nanocomposites: An Efficient Catalyst for Additive-Base-Free Aerial Oxidation of Various Kinds of Alcohols