scholarly journals Monometallic Cerium Layered Double Hydroxide Supported Pd-Ni Nanoparticles as High Performance Catalysts for Lignin Hydrogenolysis

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 691
Author(s):  
Tibo De Saegher ◽  
Jeroen Lauwaert ◽  
Jorku Hanssen ◽  
Els Bruneel ◽  
Matthias Van Zele ◽  
...  
Keyword(s):  
High Performance ◽  
Model Compound ◽  
Ether Linkage ◽  
Benzyl Phenyl Ether ◽  
Double Hydroxide ◽  
Double Hydroxides ◽  
Compositional Properties ◽  
N2 Sorption ◽  
Supported Pd ◽  
Xrf Analyses

Monometallic cerium layered double hydroxides (Ce-LDH) supports were successfully synthesized by a homogeneous alkalization route driven by hexamethylenetetramine (HMT). The formation of the Ce-LDH was confirmed and its structural and compositional properties studied by XRD, SEM, XPS, iodometric analyses and TGA. HT-XRD, N2-sorption and XRF analyses revealed that by increasing the calcination temperature from 200 to 800 °C, the Ce-LDH material transforms to ceria (CeO2) in four distinct phases, i.e., the loss of intramolecular water, dehydroxylation, removal of nitrate groups and removal of sulfate groups. When loaded with 2.5 wt% palladium (Pd) and 2.5 wt% nickel (Ni) and calcined at 500 °C, the PdNi-Ce-LDH-derived catalysts strongly outperform the PdNi-CeO2 benchmark catalyst in terms of conversion as well as selectivity for the hydrogenolysis of benzyl phenyl ether (BPE), a model compound for the α-O-4 ether linkage in lignin. The PdNi-Ce-LDH catalysts showed full selectivity towards phenol and toluene while the PdNi-CeO2 catalysts showed additional oxidation of toluene to benzoic acid. The highest BPE conversion was observed with the PdNi-Ce-LDH catalyst calcined at 600 °C, which could be related to an optimum in morphological and compositional characteristics of the support.

scholarly journals Polymer/Iron-Based Layered Double Hydroxides as Multifunctional Wound Dressings

Pharmaceutics ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 1130
Author(s):  
Mariana Pires Figueiredo ◽  
Ana Borrego-Sánchez ◽  
Fátima García-Villén ◽  
Dalila Miele ◽  
Silvia Rossi ◽  
...  
Keyword(s):  
Drug Release ◽  
High Performance ◽  
Mechanical Performance ◽  
Release Kinetics ◽  
Wound Dressings ◽  
In Vitro Drug Release ◽  
Improved Performance ◽  
Double Hydroxide ◽  
Double Hydroxides

This work presents the development of multifunctional therapeutic membranes based on a high-performance block copolymer scaffold formed by polyether (PE) and polyamide (PA) units (known as PEBA) and layered double hydroxide (LDH) biomaterials, with the aim to study their uses as wound dressings. Two LDH layer compositions were employed containing Mg2+ or Zn2+, Fe3+ and Al3+ cations, intercalated with chloride anions, abbreviated as Mg-Cl or Zn-Cl, or intercalated with naproxenate (NAP) anions, abbreviated as Mg-NAP or Zn-NAP. Membranes were structurally and physically characterized, and the in vitro drug release kinetics and cytotoxicity assessed. PEBA-loading NaNAP salt particles were also prepared for comparison. Intercalated NAP anions improved LDH–polymer interaction, resulting in membranes with greater mechanical performance compared to the polymer only or to the membranes containing the Cl-LDHs. Drug release (in saline solution) was sustained for at least 8 h for all samples and release kinetics could be modulated: a slower, an intermediate and a faster NAP release were observed from membranes containing Zn-NAP, NaNAP and Mg-NAP particles, respectively. In general, cell viability was higher in the presence of Mg-LDH and the membranes presented improved performance in comparison with the powdered samples. PEBA containing Mg-NAP sample stood out among all membranes in all the evaluated aspects, thus being considered a great candidate for application as multifunctional therapeutic dressings.

scholarly journals Investigation of Ni–Fe–Cu-Layered Double Hydroxide Catalysts in Steam Reforming of Toluene as a Model Compound of Biomass Tar

Processes ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 76
Author(s):  
David Díez ◽  
Ana Urueña ◽  
Gregorio Antolín
Keyword(s):  
Steam Reforming ◽  
Model Compound ◽  
Low Carbon ◽  
Molar Ratios ◽  
Different Temperatures ◽  
Biomass Tar ◽  
Steam Reforming Of Toluene ◽  
Double Hydroxide ◽  
Double Hydroxides ◽  
Gas Conversion

This work focused on the synthesis of a catalyst based on layered double hydroxides with a molar cation concentration Ni/Cu/Fe/Mg/Al of 30/5/5/40/20 and its performance in the steam reforming of toluene as a model compound of biomass tar. Its performance at different temperatures (500, 600, 700, 800, and 900 °C) and steam/carbon molar ratios (S/C ratios) (1, 2, 4, 6, 8) was studied. The contact time used was 0.32 g h mol−1. The catalyst obtained allowed us to reach 98–99.87% gas conversion of toluene with a low carbon deposition on catalyst surface (1.4 wt %) at 800 °C and S/C = 4. In addition, conversions in the range of 600–700 °C were higher than 80% and 90%, respectively, and the type of carbon deposited on the catalyst was found to be filamentous, which did not significantly reduce the performance of the catalyst.

In-Situ Embedding of Cobaltous Sulfide Quantum Dots among Transition Metal Layered Double Hydroxide for High Performance All-Solid-State Asymmetric Supercapacitors

2021 ◽  
Author(s):  
Zhiqiang Liu ◽  
Yanling Qiu ◽  
Aitang Zhang ◽  
Wenrong Yang ◽  
Colin J. Barrow ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Solid State ◽  
Active Sites ◽  
High Performance ◽  
Metal Species ◽  
Asymmetric Supercapacitors ◽  
Double Hydroxide ◽  
Double Hydroxides ◽  
In Situ Embedding

Layered double hydroxides (LDHs) are widely used as cathode materials for supercapacitors (SCs) thanks to their many advantages. However, the single metal species with limited active sites limit the further...

Physical - Chemical Issues of Cephalosporin Intercalated Nanoparticles for Life - Threatening Infections Treatment

2001 ◽  
Vol 71 (3) ◽  
pp. 342-349
Author(s):  
Lucian Eva ◽  
Letitia Doina Duceac ◽  
Liviu Stafie ◽  
Constantin Marcu ◽  
Geta Mitrea ◽  
...  
Keyword(s):  
Chemical Characterization ◽  
Advanced Characterization ◽  
Generation Cephalosporin ◽  
Fourth Generation ◽  
Exchange Method ◽  
Physico Chemical ◽  
Life Threatening ◽  
Double Hydroxide ◽  
Double Hydroxides

The fourth generation cephalosporin antibacterial agent, cefepime, was loaded into layered double hydroxides for enhancing antibiotic efficiency, reducing side effects, as well as achieving the sustained release property. The intercalation of antibiotic into the inter-gallery of ZnAl-layered double hydroxide (LDH) was carried out using ion exchange method, by this constituting a nano-sized organic-inorganic hybrid material for a controlled release novel formulation. Although cefepime is a broad spectrum antibiotic, it has various adverse effects and a significant degradation rate. Thus, the preparation and physico-chemical characterization of nanomaterials able to intercalate this drug is an important study for medical and pharmaceutical field. The antibiotic inclusion into LDHs nanostructure was confirmed by advanced characterization techniques and the release profile of cefepime was analysed with the respect to pH of the simulated media.

scholarly journals Postsynthetic treatment of nickel–iron layered double hydroxides for the optimum catalysis of the oxygen evolution reaction

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Daire Tyndall ◽  
Sonia Jaskaniec ◽  
Brian Shortall ◽  
Ahin Roy ◽  
Lee Gannon ◽  
...  
Keyword(s):  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Size Control ◽  
Operating Conditions ◽  
Nickel Iron ◽  
Treatment Techniques ◽  
Site Density ◽  
Synthetic Approaches ◽  
Double Hydroxide ◽  
Double Hydroxides

AbstractNickel–iron-layered double hydroxide (NiFe LDH) platelets with high morphological regularity and submicrometre lateral dimensions were synthesized using a homogeneous precipitation technique for highly efficient catalysis of the oxygen evolution reaction (OER). Considering edge sites are the point of activity, efforts were made to control platelet size within the synthesized dispersions. The goal is to controllably isolate and characterize size-reduced NiFe LDH particles. Synthetic approaches for size control of NiFe LDH platelets have not been transferable based on published work with other LDH materials and for that reason, we instead use postsynthetic treatment techniques to improve edge-site density. In the end, size-reduced NiFe LDH/single-wall carbon nanotube (SWCNT) composites allowed to further reduce the OER overpotential to 237 ± 7 mV (<L> = 0.16 ± 0.01 μm, 20 wt% SWCNT), which is one of the best values reported to date. This approach as well improved the long-term activity of the catalyst in operating conditions.

scholarly journals Layered double hydroxide membrane with high hydroxide conductivity and ion selectivity for energy storage device

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jing Hu ◽  
Xiaomin Tang ◽  
Qing Dai ◽  
Zhiqiang Liu ◽  
Huamin Zhang ◽  
...  
Keyword(s):  
Energy Storage ◽  
High Performance ◽  
Ion Selectivity ◽  
Storage Device ◽  
Hydroxyl Groups ◽  
Flow Battery ◽  
Energy Storage Devices ◽  
Storage Devices ◽  
Ions Transport ◽  
Double Hydroxides

AbstractMembranes with fast and selective ions transport are highly demanded for energy storage devices. Layered double hydroxides (LDHs), bearing uniform interlayer galleries and abundant hydroxyl groups covalently bonded within two-dimensional (2D) host layers, make them superb candidates for high-performance membranes. However, related research on LDHs for ions separation is quite rare, especially the deep-going study on ions transport behavior in LDHs. Here, we report a LDHs-based composite membrane with fast and selective ions transport for flow battery application. The hydroxide ions transport through LDHs via vehicular (standard diffusion) & Grotthuss (proton hopping) mechanisms is uncovered. The LDHs-based membrane enables an alkaline zinc-based flow battery to operate at 200 mA cm−2, along with an energy efficiency of 82.36% for 400 cycles. This study offers an in-depth understanding of ions transport in LDHs and further inspires their applications in other energy-related devices.

scholarly journals A class of novel luminescent layered double hydroxide nanotubes

RSC Advances ◽  
2021 ◽  
Vol 11 (40) ◽  
pp. 24747-24751
Author(s):  
Dimy Nanclares ◽  
Alysson F. Morais ◽  
Thainá Calaça ◽  
Ivan G. N. Silva ◽  
Danilo Mustafa
Keyword(s):  
Layered Double Hydroxide ◽  
Layered Double Hydroxides ◽  
Soft Templating ◽  
Double Hydroxide ◽  
Double Hydroxides

The incorporation of triply charged lanthanides in layered double hydroxides (LDHs) enables the curvature of the LDH sheets, unlocking the possibility of using a soft templating strategy to produce a class of luminescent, hierarchical LDH nanotubes.

Model Compound Approach for Polymer-Metal InterFaces: ESCA Studies

1984 ◽  
Vol 40 ◽  
Author(s):  
P. N. Sanda ◽  
J. W. Bartha ◽  
B. D. Silverman ◽  
P. S. Ho ◽  
A. R. Rossi
Keyword(s):  
Model Compound ◽  
Amino Groups ◽  
Ether Linkage ◽  
Cu Films ◽  
Polymer Metal ◽  
Terminal Amino ◽  
Metal Interfaces ◽  
Imide Group

AbstractESCA studies of two molecules which are similar in structure to the PMDA and ODA constituents of the PMDA-ODA polyimide monomer are discussed. Their interaction with in-situ evaporated Cr and Cu films are compared. The PMDA model compound interacts with Cr through the imide group, while very little interaction is observed with Cu. The ODA model compound (oxydianiline) interacts with Cr via the ether linkage and the terminal amino groups, whereas very little interaction is observed with Cu.

Sign in / Sign up

Export Citation Format

Share Document