The role of oxygen vacancies in TT-Nb2O5 nanoparticles for the photoconversion of glycerol into solketal

Gomes, Gustavo H.M.; Gabriel, José Balena; Bruziquesi, Carlos Giovani Oliveira; Victoria, Henrique V.; Oliveira, Luiz C.A.; Mohallem, Nelcy Della Santina

doi:10.1016/j.ceramint.2023.01.068

Cited by 10 publications

(5 citation statements)

References 66 publications

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“…38 According to the accepted theory, Nb 5+ ions will accept one of the electrons from an F centre, transitioning to the Nb 4+ state and leaving behind an F + centre. 20,36 O V + 2e − → FF + Nb 5+ → F + + Nb 4+ V 0 + e − → F + Nb 5+ + e − → Nb 4+ …”

Section: Resultsmentioning

confidence: 99%

“…This broadening may be attributed to the reduction of Nb 5+ states and the generation of Nb 4+ states due to the formation of oxygen vacancies. 20 The deconvoluted spectra revealed additional peaks at 208.3 eV and 205.8 eV, which are associated with Nb 4+ states. As oxygen vacancies are formed within the nanoparticles, Nb 5+ ions in close proximity to the vacancies acquire an electron from the oxygen vacancy (O V ), leading to a transformation into Nb 4+ states.…”

Section: Xps Analysismentioning

confidence: 94%

“…Previous studies by Gomes et al have reported that vacancies, such as oxygen vacancies or cation substitutions, can lead to similar distortions and high strain values. 20 The evolution of an amorphous structure in the sample from a high crystalline phase greatly helps in boosting its SERS performance by creating more adsorption sites and providing more charge transfer pathways through the formation of defect-induced energy levels in the forbidden energy region. Our results are consistent with the previous reports based on other oxide materials.…”

Section: Morphology Studiesmentioning

confidence: 99%

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Evidence of oxygen vacancy-mediated ultrahigh SERS sensitivity of Niobium pentoxide nanoparticles through defect engineering: theoretical and experimental studies

Ghosal,

Bora,

Giri

2024

Nanoscale

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Section: Resultsmentioning

confidence: 99%

Section: Xps Analysismentioning

confidence: 94%

Section: Morphology Studiesmentioning

confidence: 99%

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Evidence of oxygen vacancy-mediated ultrahigh SERS sensitivity of Niobium pentoxide nanoparticles through defect engineering: theoretical and experimental studies

Ghosal,

Bora,

Giri

2024

Nanoscale

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“…In this paper, the authors developed a dual process in which the catalyst first converts isopropyl alcohol to acetone, generating H + as a by-product, which then catalyzes the synthesis of solketal. The results showed glycerol conversions of 47.8%, with a selectivity towards solketal of 69.8% [240].…”

Section: Latest Technological Advancesmentioning

confidence: 97%

Transformations of Glycerol into High-Value-Added Chemical Products: Ketalization and Esterification Reactions

Perez,

Gatti,

Santori

et al. 2023

Reactions

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Biomass allows us to obtain energy and high-value-added compounds through the use of different physical and chemical processes. The glycerol obtained as a by-product in the synthesis of biodiesel is considered a biomass compound that has the potential to be used as a raw material to obtain different chemical products for industry. The development and growth of the biodiesel industry allows for the projection of glycerol biorefineries around these plants that efficiently and sustainably integrate the biodiesel production process together with the glycerol transformation processes. This work presents a review of the ketalization and esterification of glycerol to obtain solketal and acetylglycerols, which are considered products of high added value for the chemical and fuel industry. First, the general aspects and mechanisms of both reactions are presented, as well as the related chemical equilibrium concepts. Subsequently, the catalysts employed are described, classifying them according to their catalytic nature (zeolites, carbons, exchange resins, etc.). The reaction conditions used are also described, and the best results for each catalytic system are presented. In addition, stability studies and the main deactivation mechanisms are discussed. Finally, the work presents the kinetic models that have been formulated to date for some of these systems. It is expected that this review work will serve as a tool for the advancement of studies on the ketalization and esterification reactions that allow for the projection of biorefineries based on glycerol as a raw material.

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“…[ 13 ] In the second work, Gomes et al reported the use of Nb 2 O 5 nanoparticles to obtain the conversion of glycerol of 47.8% as well as the selectivity to solketal (69.8%). [ 14 ] In both works, the 6‐membered ring (5,5‐dimethyl‐1,3‐dioxane, DMDO) (Figure 1) was also obtained and they do not include studies of recyclability of the catalysts. Finally, Martín‐Gómez et al have recently reported that Bi 2 WO 6 was a very active catalyst when the reaction was conducted in the presence of p ‐benzoquinone obtaining glycerol conversions close to 80% after 8 h in reaction.…”

Section: Introductionmentioning

confidence: 99%

Metal‐ and Acid‐Free Photocatalytic Approach Using Quinone‐Based Hyper‐Crosslinked Porous Catalysts for the Valorization of Glycerol into Solketal

Matarín,

González‐Aguilera,

Ferrer

et al. 2024

Solar RRL

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Two metal‐ and acid‐free anthracene and anthraquinone‐based photocatalysts (HCP‐AQ‐2Ph and HCP‐AN‐2Ph) are synthesized and used for the effective acetalization of glycerol to obtain selectively solketal, an added‐value compound with several industrial applications and high demand as an oxygenated additive of fuels. HCP‐AQ‐2Ph and HCP‐AN‐2Ph were prepared by a Friedel‐Crafts coupling reaction between the anthraquinone (AQ) or anthracene (A) and biphenyl (2Ph) as co‐monomer which led to the formation of high thermally stable hyper‐crosslinked porous networks with specific surface areas of 295 and 596 m2.g‐1 respectively. Initial tests suggested that HCP‐AN‐2Ph is a less efficient catalyst compared to HCP‐AQ‐2Ph. However, subsequent runs indicate that during the first trial, the anthracene units are oxidized, resulting in a catalyst (HCP‐AN(OX)‐2Ph) just as effective as the anthraquinone‐based one. The quantitative and selective conversion of glycerol into solketal is achieved in just 3 h using a 4wt% catalyst and maintaining this catalytic performance for at least 5 cycles. In addition, the process can be scaled allowing the obtaining of solketal with high purity on a gram scale. These results place these catalysts among the most effective for the selective production of solketal from glycerol compared to previously reported metal‐or acid‐catalyzed reaction.This article is protected by copyright. All rights reserved.

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The role of oxygen vacancies in TT-Nb2O5 nanoparticles for the photoconversion of glycerol into solketal

Cited by 10 publications

References 66 publications

Evidence of oxygen vacancy-mediated ultrahigh SERS sensitivity of Niobium pentoxide nanoparticles through defect engineering: theoretical and experimental studies

Evidence of oxygen vacancy-mediated ultrahigh SERS sensitivity of Niobium pentoxide nanoparticles through defect engineering: theoretical and experimental studies

Transformations of Glycerol into High-Value-Added Chemical Products: Ketalization and Esterification Reactions

Metal‐ and Acid‐Free Photocatalytic Approach Using Quinone‐Based Hyper‐Crosslinked Porous Catalysts for the Valorization of Glycerol into Solketal

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