scholarly journals Selective Oxidation of HMF via Catalytic and Photocatalytic Processes Using Metal-Supported Catalysts

Molecules ◽  
2018 ◽  
Vol 23 (11) ◽  
pp. 2792 ◽  
Author(s):  
Alice Lolli ◽  
Valeriia Maslova ◽  
Danilo Bonincontro ◽  
Francesco Basile ◽  
Simona Ortelli ◽  
...  
Keyword(s):  
Freeze Drying ◽  
Mixed Oxides ◽  
Supported Catalysts ◽  
High Surface ◽  
Product Distribution ◽  
Oxidation Reactions ◽  
Surface Areas ◽  
Photocatalytic Application ◽  
Phase Oxidation ◽  
Spray Freeze Drying

In this study, 5-hydroxymethylfurfural (HMF) oxidation was carried out via both the catalytic and the photocatalytic approach. Special attention was devoted to the preparation of the TiO2-based catalysts, since this oxide has been widely used for catalytic and photocatalytic application in alcohol oxidation reactions. Thus, in the catalytic process, the colloidal heterocoagulation of very stable sols, followed by the spray-freeze-drying (SFD) approach, was successfully applied for the preparation of nanostructured porous TiO2-SiO2 mixed-oxides with high surface areas. The versatility of the process made it possible to encapsulate Pt particles and use this material in the liquid-phase oxidation of HMF. The photocatalytic activity of a commercial titania and a homemade oxide prepared with the microemulsion technique was then compared. The influence of gold, base addition, and oxygen content on product distribution in the photocatalytic process was evaluated.

scholarly journals Nickel Phosphide Catalysts as Efficient Systems for CO2 Upgrading via Dry Reforming of Methane

Catalysts ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 446
Author(s):  
Miriam González-Castaño ◽  
Estelle le Saché ◽  
Cameron Berry ◽  
Laura Pastor-Pérez ◽  
Harvey Arellano-García ◽  
...  
Keyword(s):  
Supported Catalysts ◽  
Lower Surface ◽  
Catalytic Performance ◽  
Dry Reforming Of Methane ◽  
Oxidation Reactions ◽  
Surface Areas ◽  
Ceo2 Sample ◽  
Conversion Rates ◽  
Ni Oxidation ◽  
Catalytic Behaviour

This work establishes the primordial role played by the support’s nature when aimed at the constitution of Ni2P active phases for supported catalysts. Thus, carbon dioxide reforming of methane was studied over three novel Ni2P catalysts supported on Al2O3, CeO2 and SiO2-Al2O3 oxides. The catalytic performance, shown by the catalysts’ series, decreased according to the sequence: Ni2P/Al2O3 > Ni2P/CeO2 > Ni2P/SiO2-Al2O3. The depleted CO2 conversion rates discerned for the Ni2P/SiO2-Al2O3 sample were associated to the high sintering rates, large amounts of coke deposits and lower fractions of Ni2P constituted in the catalyst surface. The strong deactivation issues found for the Ni2P/CeO2 catalyst, which also exhibited small amounts of Ni2P species, were majorly associated to Ni oxidation issues. Along with lower surface areas, oxidation reactions might also affect the catalytic behaviour exhibited by the Ni2P/CeO2 sample. With the highest conversion rate and optimal stabilities, the excellent performance depicted by the Ni2P/Al2O3 catalyst was mostly related to the noticeable larger fractions of Ni2P species established.

Effect of Different Silicate Supports on the Catalytic Performance of MoVTeO Mixed Oxides in Partial Oxidation of Isobutane

2014 ◽  
Vol 12 (1) ◽  
pp. 623-628
Author(s):  
Jing Hu ◽  
Zhifang Li ◽  
Xiaoyuan Yang ◽  
Wenli Ding ◽  
Jingqi Guan
Keyword(s):  
Catalytic Activity ◽  
Specific Surface ◽  
Surface Area ◽  
Partial Oxidation ◽  
Mixed Oxides ◽  
Supported Catalysts ◽  
Catalytic Performance ◽  
Surface Areas ◽  
Specific Surface Areas ◽  
Mcm 41

Abstract A series of 5% MoV0.3Te0.25 supported on different silicates (i.e. SiO2, HMS, MCM-41, and MCM-48) have been prepared, characterized, and tested as catalysts in the partial oxidation of isobutane to methacrolein. Characterization results showed that the supports almost kept intact structures after supporting 5 wt.% MoV0.3Te0.25 and the supported catalysts had large specific surface areas. Catalytic tests showed that the specific surface area played a key role in the catalytic activity for the supported catalysts.

Preparation and characterization of porous TiO2-SiO2 mixed oxide

2004 ◽  
Vol 848 ◽  
Author(s):  
Ang Thiam Peng ◽  
Zhong Ziyi ◽  
James Highfield
Keyword(s):  
Electron Microscopy ◽  
Mixed Oxide ◽  
Mixed Oxides ◽  
Structural Information ◽  
High Surface ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Surface Areas ◽  
Transmission Electron

ABSTRACTA study on the comparison of porous TiO2-SiO2 mixed oxides synthesized variously via the “amine directed” method is reported. The amine capping groups were octylamine, dodecylamine, octyldecylamine, aniline, and isobutylamine. The mixed oxide is characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), infrared spectroscopy (IR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and Brunauer-Emmett-Teller analysis (BET). While XRD, SEM and TEM provide mainly (bulk) structural information on the mixed oxide preparations, BET (N2 physisorption) probes into their surface area and texture. IR evidence suggests that intimate chemical mixing of both oxides has occurred, while BET measurements show that high surface areas are attainable and that the mixed oxide is more thermally stable than pure (control) samples of TiO2.

A Highly Crystalline Anthracene-Based MOF-74 Series Featuring Electrical Conductivity and Luminescence

2019 ◽  
Author(s):  
Patricia Scheurle ◽  
Andre Mähringer ◽  
Andreas Jakowetz ◽  
Pouya Hosseini ◽  
Alexander Richter ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Metal Ions ◽  
Light Emission ◽  
Block Design ◽  
High Surface ◽  
Visible Spectrum ◽  
Building Blocks ◽  
Divalent Metal Ions ◽  
Conductivity Enhancement ◽  
Surface Areas

Recently, a small group of metal-organic frameworks (MOFs) has been discovered featuring substantial charge transport properties and electrical conductivity, hence promising to broaden the scope of potential MOF applications in fields such as batteries, fuel cells and supercapacitors. In combination with light emission, electroactive MOFs are intriguing candidates for chemical sensing and optoelectronic applications. Here, we incorporated anthracene-based building blocks into the MOF-74 topology with five different divalent metal ions, that is, Zn2+, Mg2+, Ni2+, Co2+ and Mn2+, resulting in a series of highly crystalline MOFs, coined ANMOF-74(M). This series of MOFs features substantial photoluminescence, with ANMOF-74(Zn) emitting across the whole visible spectrum. The materials moreover combine this photoluminescence with high surface areas and electrical conductivity. Compared to the original MOF-74 materials constructed from 2,5-dihydroxy terephthalic acid and the same metal ions Zn2+, Mg2+, Ni2+, Co2+ and Mn2+, we observed a conductivity enhancement of up to six orders of magnitude. Our results point towards the importance of building block design and the careful choice of the embedded MOF topology for obtaining materials with desired properties such as photoluminescence and electrical conductivity.

scholarly journals Intratracheal inoculation of AHc vaccine induces protection against aerosolized botulinum neurotoxin A challenge in mice

npj Vaccines ◽  
2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Changjiao Gan ◽  
Wenbo Luo ◽  
Yunzhou Yu ◽  
Zhouguang Jiao ◽  
Sha Li ◽  
...  
Keyword(s):  
Bronchoalveolar Lavage ◽  
Clostridium Botulinum ◽  
Freeze Drying ◽  
Botulinum Neurotoxin ◽  
Secretory Iga ◽  
Immune Protection ◽  
Dry Powder ◽  
Botulinum Neurotoxin A ◽  
Spray Freeze Drying

AbstractBotulinum neurotoxin (BoNT), produced by Clostridium botulinum, is generally known to be the most poisonous of all biological toxins. In this study, we evaluate the protection conferred by intratracheal (i.t.) inoculation immunization with recombinant Hc subunit (AHc) vaccines against aerosolized BoNT/A intoxication. Three AHc vaccine formulations, i.e., conventional liquid, dry powder produced by spray freeze drying, and AHc dry powder reconstituted in water are prepared, and mice are immunized via i.t. inoculation or subcutaneous (s.c.) injection. Compared with s.c.-AHc-immunized mice, i.t.-AHc-immunized mice exhibit a slightly stronger protection against a challenge with 30,000× LD50 aerosolized BoNT/A. Of note, only i.t.-AHc induces a significantly higher level of toxin-neutralizing mucosal secretory IgA (SIgA) production in the bronchoalveolar lavage of mice. In conclusion, our study demonstrates that the immune protection conferred by the three formulations of AHc is comparable, while i.t. immunization of AHc is superior to s.c. immunization against aerosolized BoNT/A intoxication.

scholarly journals Mitigating the Agglomeration of Nanofiller in a Mixed Matrix Membrane by Incorporating an Interface Agent

Membranes ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 328
Author(s):  
Manh-Tuan Vu ◽  
Gloria M. Monsalve-Bravo ◽  
Rijia Lin ◽  
Mengran Li ◽  
Suresh K. Bhatia ◽  
...  
Keyword(s):  
Gas Separation ◽  
Polymer Matrix ◽  
Ion Beam ◽  
High Surface ◽  
Mixed Matrix Membrane ◽  
Mechanical And Thermal Properties ◽  
Separation Membranes ◽  
Surface Areas ◽  
Separation Membrane ◽  
Focus Ion Beam

Nanodiamonds (ND) have recently emerged as excellent candidates for various applications including membrane technology due to their nanoscale size, non-toxic nature, excellent mechanical and thermal properties, high surface areas and tuneable surface structures with functional groups. However, their non-porous structure and strong tendency to aggregate are hindering their potential in gas separation membrane applications. To overcome those issues, this study proposes an efficient approach by decorating the ND surface with polyethyleneimine (PEI) before embedding it into the polymer matrix to fabricate MMMs for CO2/N2 separation. Acting as both interfacial binder and gas carrier agent, the PEI layer enhances the polymer/filler interfacial interaction, minimising the agglomeration of ND in the polymer matrix, which is evidenced by the focus ion beam scanning electron microscopy (FIB-SEM). The incorporation of PEI into the membrane matrix effectively improves the CO2/N2 selectivity compared to the pristine polymer membranes. The improvement in CO2/N2 selectivity is also modelled by calculating the interfacial permeabilities with the Felske model using the gas permeabilities in the MMM. This study proposes a simple and effective modification method to address both the interface and gas selectivity in the application of nanoscale and non-porous fillers in gas separation membranes.

scholarly journals Bio-DEE Synthesis and Dehydrogenation Coupling of Bio-Ethanol to Bio-Butanol over Multicomponent Mixed Metal Oxide Catalysts

Catalysts ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 660
Author(s):  
Izabela S. Pieta ◽  
Alicja Michalik ◽  
Elka Kraleva ◽  
Dusan Mrdenovic ◽  
Alicja Sek ◽  
...  
Keyword(s):  
Active Sites ◽  
Internal Combustion Engines ◽  
Mixed Oxides ◽  
Catalyst Activity ◽  
Product Distribution ◽  
Coke Deposition ◽  
Precipitation Method ◽  
Mixed Metal Oxide ◽  
Low Carbon ◽  
Municipal Solid Wastes

Within the Waste2Fuel project, innovative, high-performance, and cost-effective fuel production methods from municipal solid wastes (MSWs) are sought for application as energy carriers or direct drop-in fuels/chemicals in the near-future low-carbon power generation systems and internal combustion engines. Among the studied energy vectors, C1-C2 alcohols and ethers are mainly addressed. This study presents a potential bio-derived ethanol oxidative coupling in the gas phase in multicomponent systems derived from hydrotalcite-containing precursors. The reaction of alcohol coupling to ethers has great importance due to their uses in different fields. The samples have been synthesized by the co-precipitation method via layered double hydroxide (LDH) material synthesis, with a controlled pH, where the M(II)/M(III) ≈ 0.35. The chemical composition and topology of the sample surface play essential roles in catalyst activity and product distribution. The multiple redox couples Ni2+/Ni3+, Cr2+/Cr3+, Mn2+/Mn3+, and the oxygen-vacant sites were considered as the main active sites. The introduction of Cr (Cr3+/Cr4+) and Mn (Mn3+/Mn4+) into the crystal lattice could enhance the number of oxygen vacancies and affect the acid/base properties of derived mixed oxides, which are considered as crucial parameters for process selectivity towards bio-DEE and bio-butanol, preventing long CH chain formation and coke deposition at the same time.

scholarly journals Post-Processing Techniques for the Improvement of Liposome Stability

Pharmaceutics ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1023
Author(s):  
Ji Young Yu ◽  
Piyanan Chuesiang ◽  
Gye Hwa Shin ◽  
Hyun Jin Park
Keyword(s):  
Freeze Drying ◽  
Protective Agent ◽  
Post Processing ◽  
Additional Process ◽  
Spray Freeze Drying ◽  
The Stability ◽  
Processing Techniques ◽  
The Impact ◽  
Self Aggregation ◽  
Liposome Stability

Liposomes have been utilized as a drug delivery system to increase the bioavailability of drugs and to control the rate of drug release at the target site of action. However, the occurrence of self-aggregation, coalescence, flocculation and the precipitation of aqueous liposomes during formulation or storage can cause degradation of the vesicle structure, leading to the decomposition of liposomes. To increase the stability of liposomes, post-processing techniques have been applied as an additional process to liposomes after formulation to remove water and generate dry liposome particles with a higher stability and greater accessibility for drug administration in comparison with aqueous liposomes. This review covers the effect of these techniques including freeze drying, spray drying and spray freeze drying on the stability, physicochemical properties and drug encapsulation efficiency of dry liposomes. The parameters affecting the properties of liposomes during the drying process are also highlighted in this review. In addition, the impact of using a protective agent to overcome such limitations of each process is thoroughly discussed through various studies.

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