Search results for "Mesoporous material"

Nanoscopic hybrid systems with a polarity-controlled gate-like scaffolding for the colorimetric signalling of long-chain carboxylates

2007

Hybrid mesoporous systems containing a gate-like ensemble functionalised with imidazolium groups and a dye are used for the selective colorimetric sensing of long-chain carboxylates. Amoros del Toro, Pedro Jose, Pedro.Amoros@uv.es

Highly dispersed encapsulated AuPd nanoparticles on ordered mesoporous carbons for the direct synthesis of H2O2 from molecular oxygen and hydrogen

2012

AuPd nanoparticles (<3 nm) have been encapsulated on the pores of a nanostructured CMK-3 carbon prepared by a nanocasting procedure. This material has been shown to be an excellent catalyst for the direct synthesis of hydrogen peroxide from molecular hydrogen and oxygen.

ChemInform Abstract: Enhanced Surface Area in Thermally Stable Pure Mesoporous TiO2.

2001

Abstract We describe here for the first time the surfactant-assisted synthesis of thermally stable mesoporous pure TiO 2 having a high surface area. Our synthetic approach to the chemistry of this system is based on the equilibrium between the hydrolysis and condensation reactions of the inorganic species and the organic–inorganic self-assembling processes. The use of titanatrane complexes helps to retard the hydrolysis and condensation reactions, thus allowing us to overcome the difficulties in preparing titanium dioxide mesoporous materials starting from highly reactive Ti-alkoxides. The mesoporous material has been characterized by TEM, XRD and N 2 adsorption–desorption isotherms and dis…

Modelling electrocatalysis of hydroquinone oxidation by nicotinamide adenine dinucleaotide coenzyme encapsulated within SBA-15 and MCM-41 mesoporous …

2006

The electrochemical response of NADH associated to two mesoporous aluminosilicates, MCM-41 and SBA-15, is described upon attachment of such materials into polymer-film electrodes. The studied materials display a significant electrocatalytic activity towards the oxidation of 1,4-dihydrobenzoquinone, H2Q. Two models for describing the electrocatalytic process, based on the general theory of mediated electrocatalysis and the Lovric and Scholz formulation of the voltammetry of microparticles are discussed. Voltammetric and chronoamperometric data indicate that the electrocatalytic process involves the formation of a surface-confined NADH–H2Q adduct in the case of SBA-15, while a surface reactio…

Relationship between intrinsic pore-wall corrugation and adsorption hysteresis of N-2, O-2, and Ar on regular mesopores

2000

Molecular mechanism of capillary condensation of acetonitrile vapor on MCM-41 with the aid of a time-correlation function analysis of IR spectroscopy

1998

Abstract The adsorption isotherm and IR spectra of acetonitrile adsorbed on MCM-41 (pore-width=3.2 nm) were measured at 303 K. The adsorption isotherm had a sharp jump at P / P 0 =0.3 without adsorption hysteresis. The CN stretching ν 2 -band of adsorbed acetonitrile had two-component α- and β-bands at 2263 and 2254 cm −1 , respectively, assigned to hydrogen-bonded molecules on surface hydroxyls of MCM-41 and physisorbed molecules in mesopores whose walls are coated with hydrogen-bonded molecules, respectively. The β-band was analyzed with a time correlation function, giving a reorientation time τ . The τ value of the adsorbed molecule before capillary condensation was smaller than that of …

Enzyme-responsive silica mesoporous supports capped with azopyridinium salts for controlled delivery applications

2012

11 páginas, 7 figuras, 3 tablas y 2 esquemas

Cathepsin-B Induced Controlled Release from Peptide-Capped Mesoporous Silica Nanoparticles

2014

New capped silica mesoporous nanoparticles for intracellular controlled cargo release within cathepsin B expressing cells are described. Nanometric mesoporous MCM-41 supports loaded with safranin O (S1-P) or doxorubicin (S2-P) containing a molecular gate based on a cathepsin B target peptidic sequence were synthesized. Solids were designed to show "zero delivery" and to display cargo release in the presence of cathepsin B enzyme, which selectively hydrolyzed in vitro the capping peptide sequence. Controlled delivery in HeLa, MEFs WT, and MEFs lacking cathepsin B cell lines were also tested. Release of safranin O and doxorubicin in these cells took place when cathepsin B was active or presen…

A photoactivated molecular gate.

2012

Light-controlled gate: A novel capped silica nanoscopic mesoporous hybrid material for photo-driven cargo release applications has been designed and prepared. The capped system, which shows a zero release, contains a photo-cleavable bulky o-methoxybenzylamine derivative. Upon irradiation at 254¿nm, photo-degradation of the o-methoxybenzylamine framework and the subsequent delivery of a fluorescent cargo were observed

Organic-Inorganic Hybrid Mesoporous Materials as Regenerable Sensing Systems for the Recognition of Nitroaromatic Explosives

2013

[EN] Fluorescent organic-inorganic mesoporous hybrid materials have been prepared and characterised, and their behaviour against nitroaromatic explosives have been tested. MCM-41 silica was used as an inorganic scaffold and pyrene (P derivative containing trialkoxysilane moieties), dansyl and fluorescein (D and F derivatives also containing trialkoxysilane groups, respectively) fluorophores have been anchored on hybrid materials by a co-condensation method to obtain a homogenous distribution of dyes into the pores of the support. Six sensing materials have been prepared, of which SP, SD, SF were hydrophilic and SPh, SDh, SFh were hydrophobic. Template-free hydrophilic materials (SP, SD, SF)…