Combining active phase and support optimization in MnO2-Au nanoflowers: Enabling high activities towards green oxidations

Silva, Anderson G. M. da; Rodrigues, Thenner Silva; Candido, Eduardo Guimarães; Freitas, Isabel C. de; Silva, Alisson Henrique Marques da; Fajardo, Humberto V.; Balzer, Rosana; Gomes, Janaina F.; Assaf, José Mansur; Oliveira, Daniela C. de; Oger, Nicolas; Paul, Sébastien; Wojcieszak, Robert; Camargo, Pedro Henrique Cury de

doi:10.1016/j.jcis.2018.06.089

Cited by 37 publications

(20 citation statements)

References 65 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Recently, Hutchings [2] has pointed out that work on improvement of catalyst performance or designing new ones must be based on deep understanding of the reaction mechanism. In the last few years, Au NPs have been deposited on several different supports (e.g., mesoporous silica [3], metal oxides [4][5][6] and carbons [7,8]) and applied as catalysts in glucose oxidation. However, glucose oxidation carried out over gold catalysts supported on zeolites belongs to the reactions whose pathways have not been fully solved [9].…”

Section: Introductionmentioning

confidence: 99%

Modification of Gold Zeolitic Supports for Catalytic Oxidation of Glucose to Gluconic Acid

et al. 2021

View full text Add to dashboard Cite

Activity of gold supported catalysts strongly depends on the type and composition of support, which determine the size of Au nanoparticles (Au NPs), gold-support interaction influencing gold properties, interaction with the reactants and, in this way, the reaction pathway. The aim of this study was to use two types of zeolites: the three dimensional HBeta and the layered two-dimensional MCM-36 as supports for gold, and modification of their properties towards the achievement of different properties in oxidation of glucose to gluconic acid with molecular oxygen and hydrogen peroxide. Such an approach allowed establishment of relationships between the activity of gold catalysts and different parameters such as Au NPs size, electronic properties of gold, structure and acidity of the supports. The zeolites were modified with (3-aminopropyl)-trimethoxysilane (APMS), which affected the support features and Au NPs properties. Moreover, the modification of the zeolite lattice with boron was applied to change the strength of the zeolite acidity. All modifications resulted in changes in glucose conversion, while maintaining high selectivity to gluconic acid. The most important findings include the differences in the reaction steps limiting the reaction rate depending on the nature of the oxidant applied (oxygen vs. H2O2), the important role of porosity of the zeolite supports, and accumulation of negative charge on Au NPs in catalytic oxidation of glucose.

show abstract

Section: Introductionmentioning

confidence: 99%

Modification of Gold Zeolitic Supports for Catalytic Oxidation of Glucose to Gluconic Acid

et al. 2021

View full text Add to dashboard Cite

show abstract

“…The O 1s XPS spectra of the MnO 2 NP/UCN and MnO 2 NP are exhibited in Figure (D), which is deconvoluted into three peaks. The peaks occurred at 529.2–530.1, 531.6–532.0, and 533.1–533.4 eV, were assigned to the lattice O (O L ) bonding to Mn ions in the [MnO 6 ] octahedron units, the O 2 or active oxygen species absorbed on the surface (O L ), and the O species of H 2 O and CO 2 physically absorbed on the surface, respectively. , As recorded in Table , the percentage of O L (O L / O T , O T = O L + O C + O A ) were 60.9%, 29.2%, 13.7%, and 37.5% for MnO 2 NP, 3MnO 2 NP/UCN, 8MnO 2 NP/UCN, and 15MnO 2 NP/UCN, respectively. Among these materials, the 8MnO 2 NP/UCN showed the lowest percentage of O L , which implied the highest concentration of oxygen vacancies in 8MnO 2 NP/UCN, corresponding to the highest percentage of surface Mn 2+ and Mn 3+ .…”

Section: Resultsmentioning

confidence: 90%

Construction of Highly Efficient 3D/2D MnO₂/g-C₃N₄ Nanocomposite in the Epoxidation of Styrene with TBHP

Zhang

et al. 2019

ACS Sustainable Chem. Eng.

View full text Add to dashboard Cite

MnO2/g-C3N4 nanocomposites were facilely synthesized by calcining the mixture of bulk g-C3N4 and MnO2 precursors. The effects of the morphology of MnO2 precursors and the mass ratio of MnO2 to g-C3N4 on the micromorphology, chemical compositions, and catalytic properties of MnO2 NP/g-C3N4 nanocomposites were studied. It was found that the 3D polyhedral morphology and multiphase polycrystalline structure of MnO2 were propitious to generate the strong interaction between MnO2 and g-C3N4, which led to the enhanced concentrations of surface low-valence Mn species, oxygen vacancies, and graphitic N species. Meanwhile, when the mass ratio of MnO2 NP to g-C3N4 was 8/100, the interface of 8MnO2NP/UCN possessed the optimum synergistic effect of MnO2 NP and g-C3N4, contributing to the superior catalytic performance of 8MnO2NP/UCN with much higher yield of styrene oxide compared to other counterparts.

show abstract

“…Plasma noble metals (such as Au, [ 296–298 ] Ag, [ 116,299–301 ] and Pt [ 302 ] ) loaded on the surface of MnO 2 can significantly improve its catalytic activity. These composites combine the excellent photoelectric properties of MnO 2 , the superior surface plasmon resonance (SPR) effect, and prominent conductivity of noble metal metals, [ 303,304 ] resulting in the following advantages: 1) the SPR effect can improve its light absorption capacity by scattering resonance photons; 2) its adequate conductivity can promote the migration and separation of carriers; and 3) plasma nanometals can generate hot electrons owing to their photothermal effect, thus providing a driving force for the catalytic reaction conducive to photocatalysis.…”

Section: Fabrication Of Mno2‐based Compositesmentioning

confidence: 99%

“…Among many catalysts, MnO 2 ‐based materials have been extensively studied in the catalyst degradation of VOCs due to their natural abundance, environmentally friendliness, low cost, and specific chemical/physical properties, including different crystal structures and suitable redox activity. Currently, the reported types of VOCs degraded by MnO 2 ‐based materials include benzene series (such as toluene, [ 166,217,226,430–438 ] benzene, [ 171,173,439–441 ] ethylbenzene, [ 442–444 ] and o ‐xylene [ 297,445–448 ] ), formaldehyde, [ 54,86,116,123,137,155,156,296,449–455 ] propane, [ 456 ] aerobic sulfide, [ 172 ] methyl mercaptan, [ 299,457 ] acetone, [ 458,459 ] etc. Among them, formaldehyde and benzene series are the most common VOC pollutants in the air that have been studied the most ( Table 3 ).…”

Section: Environmental Applicationsmentioning

confidence: 99%

MnO₂‐Based Materials for Environmental Applications

et al. 2021

View full text Add to dashboard Cite

Manganese dioxide (MnO2) is a promising photo–thermo–electric‐responsive semiconductor material for environmental applications, owing to its various favorable properties. However, the unsatisfactory environmental purification efficiency of this material has limited its further applications. Fortunately, in the last few years, significant efforts have been undertaken for improving the environmental purification efficiency of this material and understanding its underlying mechanism. Here, the aim is to summarize the recent experimental and computational research progress in the modification of MnO2 single species by morphology control, structure construction, facet engineering, and element doping. Moreover, the design and fabrication of MnO2‐based composites via the construction of homojunctions and MnO2/semiconductor/conductor binary/ternary heterojunctions is discussed. Their applications in environmental purification systems, either as an adsorbent material for removing heavy metals, dyes, and microwave (MW) pollution, or as a thermal catalyst, photocatalyst, and electrocatalyst for the degradation of pollutants (water and gas, organic and inorganic) are also highlighted. Finally, the research gaps are summarized and a perspective on the challenges and the direction of future research in nanostructured MnO2‐based materials in the field of environmental applications is presented. Therefore, basic guidance for rational design and fabrication of high‐efficiency MnO2‐based materials for comprehensive environmental applications is provided.

show abstract

Combining active phase and support optimization in MnO2-Au nanoflowers: Enabling high activities towards green oxidations

Cited by 37 publications

References 65 publications

Modification of Gold Zeolitic Supports for Catalytic Oxidation of Glucose to Gluconic Acid

Modification of Gold Zeolitic Supports for Catalytic Oxidation of Glucose to Gluconic Acid

Construction of Highly Efficient 3D/2D MnO₂/g-C₃N₄ Nanocomposite in the Epoxidation of Styrene with TBHP

MnO₂‐Based Materials for Environmental Applications

Contact Info

Product

Resources

About

Combining active phase and support optimization in MnO2-Au nanoflowers: Enabling high activities towards green oxidations

Cited by 37 publications

References 65 publications

Modification of Gold Zeolitic Supports for Catalytic Oxidation of Glucose to Gluconic Acid

Modification of Gold Zeolitic Supports for Catalytic Oxidation of Glucose to Gluconic Acid

Construction of Highly Efficient 3D/2D MnO2/g-C3N4 Nanocomposite in the Epoxidation of Styrene with TBHP

MnO2‐Based Materials for Environmental Applications

Contact Info

Product

Resources

About

Construction of Highly Efficient 3D/2D MnO₂/g-C₃N₄ Nanocomposite in the Epoxidation of Styrene with TBHP

MnO₂‐Based Materials for Environmental Applications