Browse
Submit Data
Databases
API
Help

Dataset Information

17 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Degradation of Formaldehyde over MnO₂/CeO₂ Hollow Spheres: Elucidating the Influence of Carbon Sphere Self-Sacrificing Templates.

ABSTRACT: Here, we prepare a MnO₂/CeO₂ hollow sphere catalyst using the carbon sphere as a self-sacrificing template for formaldehyde (HCHO) removal. In the feed gas of 20 ppm of HCHO (balanced by N₂) + 20 vol % O₂, a HCHO removal efficiency of 70% was achieved at 20 °C and full conversion was reached at around 47 °C at GHSV = 50,000 mL (g_cat h)^-1 for MnO₂/CeO₂ hollow spheres. The catalytic performance and structural and chemical properties of MnO₂/CeO₂ hollow spheres for the removal of core carbon spheres were explored, and the influence of using the carbon sphere as a self-sacrificing template was proved by comparing with carbon@MnO₂/CeO₂ (a core carbon sphere with a MnO₂/CeO₂ shell) and nonmorphologic MnO₂/CeO₂. The properties of the MnO₂/CeO₂ hollow spheres are significantly improved compared to carbon@MnO₂/CeO₂ (removal efficiency of 45% at 150 °C) and MnO₂/CeO₂ (removal efficiency of 46% at 20 °C) as a result of an evolution in the interaction between Mn/Ce and carbon. This increase in the interaction strength seems to (i) increase the oxygen vacancy, (ii) promote the oxygen species mobility, and (iii) improve the chemical stability of the MnO₂/CeO₂ hollow spheres. We believe that these results are beneficial to the fabrication of binary transition metal oxides and applications of them in HCHO removal.

SUBMITTER: Zhu C

PROVIDER: S-EPMC8717371 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Spherical Polyelectrolyte Brushes as Templates to Prepare Hollow Silica Spheres Encapsulating Metal Nanoparticles.

Project description:Integrating hollow silica spheres with metal nanoparticles to fabricate multifunctional hybrid materials has attracted increasing attention in catalysis, detection, and drug delivery. Here, we report a simple and general method to prepare hollow silica spheres encapsulating silver nanoparticles (Ag@SiO2) based on spherical polyelectrolyte brushes (SPB), which consist of a polystyrene core and densely grafted poly (acrylic acid) (PAA) chains. SPB were firstly used as nanoreactors to generate silver nanoparticles in situ and then used as sacrificial templates to prepare hybrid hollow silica spheres. The resulted Ag@SiO2 composites exhibit high catalytic activity and good reusability for the reduction of 4-nitrophenol to 4-aminophenol by NaBH4. More importantly, this developed approach can be extended to the encapsulation of other metal nanoparticles such as gold nanoparticles into the hollow silica spheres. This work demonstrates that SPB are promising candidates for the preparation of hollow spheres with encapsulated metal nanoparticles and the resulted hybrid spheres show great potential applications in catalysis.

| S-EPMC7221898 | biostudies-literature

Facile Hydrothermal Fabrication of Nano-Oxide Hollow Spheres using Monosaccharides as Sacrificial Templates.

Project description: Not available

| S-EPMC4380956 | biostudies-literature

Spatial separation of oxidation and reduction co-catalysts for efficient charge separation: Pt@TiO2@MnO x hollow spheres for photocatalytic reactions.

Project description:Efficient charge separation is a critical factor for solar energy conversion by heterogeneous photocatalysts. This paper describes the complete spatial separation of oxidation and reduction cocatalysts to enhance the efficacy of charge separation and surface reaction. Specifically, we design Pt@TiO2@MnO x hollow spheres (PTM-HSs) with Pt and MnO x loaded onto the inner and outer surface of TiO2 shells, respectively. Pt favours electron trapping, while MnO x tends to collect holes. Upon generation from TiO2, electrons and holes flow inward and outward of the spherical photocatalyst, accumulating on the corresponding cocatalysts, and then take part in redox reactions. Combined with other advantages, such as the large surface area and appropriate pore size, the PTM-HSs exhibit high efficiency for the photocatalytic oxidation of water and benzyl alcohol. The mechanism of the oxidation process of benzyl alcohol over the photocatalyst is also presented.

| S-EPMC5530359 | biostudies-literature

Hollow PdAg-CeO2 heterodimer nanocrystals as highly structured heterogeneous catalysts.

Project description:In the present work, hollow PdAg-CeO2 heterodimer nanocrystals (NCs) were prepared and tested as catalysts for the selective hydrogenation of alkynes. These nanostructures combine for the first time the beneficial effect of alloying Pd with Ag in a single NC hollow domain with the formation of active sites at the interface with the CeO2 counterpart in an additive manner. The PdAg-CeO2 NCs display excellent alkene selectivity for aliphatic alkynes. For the specific case of hydrogenation of internal alkynes such as 4-octyne, very low over-hydrogenation and isomerization products were observed over a full conversion regime, even after prolonged reaction times. These catalytic properties were remarkably superior in comparison to standard catalysts. The promotion of Ag on the moderation of the reactivity of the Pd phase, in combination with the creation of interfacial sites with the CeO2 moiety in the same nanostructure, is pointed as the responsible of such a remarkable catalytic performance.

| S-EPMC6906419 | biostudies-literature

Synthesis of CuO and Cu3N Nanoparticles in and on Hollow Silica Spheres.

Project description:Copper oxide nanoparticles within hollow mesoporous silica spheres were prepared by binding/adsorbing Cu2+ or [Cu(NH3)4(H2O)2]2+ ions on the surface of carbon spheres, followed by formation of a mesoporous silica shell by sol-gel processing and calcination in air. The CuO nanoparticles can subsequently be converted into Cu3N nanoparticles by nitridation with ammonia. The effect of the different copper precursors, i.e. Cu2+ and [Cu(NH3)4(H2O)2]2+, on the nanocomposites was studied. CuO nanoparticles on the outer surface of hollow silica spheres were obtained by thermal treatment of hollow CuSiO3 spheres in air. Nitridation of the CuSiO3 spheres with ammonia resulted in Cu3N@SiO2 composites, with aggregated Cu3N nanoparticles on hollow silica spheres.

| S-EPMC3688256 | biostudies-literature

Hierarchically Structured CeO2 Catalyst Particles From Nanocellulose/Alginate Templates for Upgrading of Fast Pyrolysis Vapors.

Project description:Hierarchically structured porous materials often exhibit advantageous functionality for many applications including catalysts, adsorbents, and filtration systems. In this study, we report a facile approach to achieve hierarchically structured, porous cerium oxide (CeO2) catalyst particles using a templating method based on nanocellulose, a class of renewable, plant-derived nanomaterials. We demonstrate the catalyst performance benefits provided by this templating method in the context of Catalytic Fast Pyrolysis (CFP) which is a promising conversion technology to produce renewable fuel and chemical products from biomass and other types of organic waste. We show that variations in the porous structures imparted by this templating method may be achieved by modifying the content of cellulose nanofibrils, cellulose nanocrystals, and alginate in the templating suspensions. Nitrogen physisorption reveals that nearly 10-fold increases in surface area can be achieved using this method with respect to commercially available cerium oxide powder. Multiscale electron microscopy further verifies that bio-derived templating can alter the morphology of the catalyst nanostructure and tune the distribution of meso- and macro-porosity within the catalyst particles while maintaining CeO2 crystal structure. CFP experiments demonstrate that the templated catalysts display substantially higher activity on a gravimetric basis than their non-templated counterpart, and that variations in the catalyst architecture can impact the distribution of upgraded pyrolysis products. Finally, we demonstrate that the templating method described here may be extended to other materials derived from metal chlorides to achieve 3-dimensional networks of hierarchical porosity.

| S-EPMC6831546 | biostudies-literature

TiO2 Hollow Spheres With Flower-Like SnO2 Shell as Anodes for Lithium-Ion Batteries.

Project description:SnO2 is a promising anode material for lithium-ion batteries due to its high theoretical specific capacity and low operation voltage. However, its poor cycling performance hinders its commercial application. In order to improve the cycling stability of SnO2 electrodes, novel flower-like SnO2/TiO2 hollow spheres were prepared by facile hydrothermal method using carbon spheres as templates. Their flower-like shell and mesoporous structure highlighted a large specific surface area and excellent ion migration performance. Their TiO2 hollow sphere matrix and 2D SnO2 nano-flakes ensured good cycle stability. The electrochemical measurements indicated that novel flower-like SnO2/TiO2 hollow spheres delivered a high specific capacity, low irreversible capacity loss and superior rate performance. After 1,000 cycles at current densities of 200 mA g-1, the capacity of the flower-like SnO2/TiO2 hollow spheres was still maintained at 720 mAh g-1. Their rate capacity reached 486 mAh g-1 when the current densities gradually increase to 2,000 mA g-1.

| S-EPMC8692286 | biostudies-literature

Self-Templated Synthesis of Ultrathin Nanosheets Constructed TiO2 Hollow Spheres with High Electrochemical Properties.

Project description:TiO2 is well-known nanomaterials and mostly used as solid nanoparticles, and normal hollow spheres for photocatalysts or electrode materials. In this study, a novel self-templated method is presented to successfully fabricate high-surface-area ultrathin nanosheets constructed TiO2 hollow spheres through the solvothermal treatment of the titanate-silicone composite particles combined with calcination. The uniquely structured hollow spheres exhibit excellent rate capability and good cycle stability even at a high current density of ≈10 C for the anode material of Li-ion battery.

| S-EPMC5102664 | biostudies-literature

MoS2 Nanosheets Supported on Hollow Carbon Spheres as Efficient Catalysts for Electrochemical Hydrogen Evolution Reaction.

Project description:Hybridizing structured carbon materials with MoS2 has been demonstrated to be an effective method to increase the electrochemical hydrogen evolution reaction (HER) activity and durability of MoS2. In this study, we report the growth of MoS2 nanosheets on the surface of uniform hollow carbon spheres (HCS) to form a hydrangea-like nanocomposite. The HCS were formed through carbonization of a phenol formaldehyde template, and the MoS2 nanosheets were grown on the HCS surfaces through a hydrothermal method. The nanocomposites have the advantages of significantly improved electrical conductivity, ease of varying the MoS2 loading, and minimizing stacking of MoS2 nanosheets, which are manifested by their remarkably improved HER performance. The well-tuned carbon-MoS2 composite shows a Tafel slope of 48.9 mV dec-1, an onset potential of -0.079 V (vs reversible hydrogen electrode), and an overpotential of 126 mV at the current density of 10 mA cm-2 after 1000 potential cycles.

| S-EPMC6641967 | biostudies-literature

Microwave-Assisted Synthesis of NiCo2O4 Double-Shelled Hollow Spheres for High-Performance Sodium Ion Batteries.

Project description:The ternary transitional metal oxide NiCo2O4 is a promising anode material for sodium ion batteries due to its high theoretical capacity and superior electrical conductivity. However, its sodium storage capability is severely limited by the sluggish sodiation/desodiation reaction kinetics. Herein, NiCo2O4 double-shelled hollow spheres were synthesized via a microwave-assisted, fast solvothermal synthetic procedure in a mixture of isopropanol and glycerol, followed by annealing. Isopropanol played a vital role in the precipitation of nickel and cobalt, and the shrinkage of the glycerol quasi-emulsion under heat treatment was responsible for the formation of the double-shelled nanostructure. The as-synthesized product was tested as an anode material in a sodium ion battery, was found to exhibit a high reversible specific capacity of 511 mAh g-1 at 100 mA g-1, and deliver high capacity retention after 100 cycles.

| S-EPMC6199058 | biostudies-literature