Search results for "porous material"
showing 10 items of 361 documents
Confined growth of carbon nanoforms in one-dimension by fusion of anthracene rings inside the pores of MCM-41
2014
We report a simple two-step procedure that uses anthracene, a cheap polyaromatic hydrocarbon with low melting point, as a molecular precursor to produce carbon nanoforms (CNFs). First, we describe the chemical synthesis of graphite from the fusion of anthracene rings at relatively low temperature (520 °C) followed by cyclodehydrogenation. Next, we extend this protocol to the synthesis of CNFs by confining the molecular precursor in a mesoporous host like MCM-41. The confined environment favors one-dimensional growth of CNFs with sizes controlled by the pores of the mesoporous host.
A prospect for computing in porous materials research: Very large fluid flow simulations
2016
Abstract Properties of porous materials, abundant both in nature and industry, have broad influences on societies via, e.g. oil recovery, erosion, and propagation of pollutants. The internal structure of many porous materials involves multiple scales which hinders research on the relation between structure and transport properties: typically laboratory experiments cannot distinguish contributions from individual scales while computer simulations cannot capture multiple scales due to limited capabilities. Thus the question arises how large domain sizes can in fact be simulated with modern computers. This question is here addressed using a realistic test case; it is demonstrated that current …
Tuning the Photocatalytic Activity of Ti-Based Metal-Organic Frameworks through Modulator Defect-Engineered Functionalization.
2022
Defect engineering is a valuable tool to tune the photocatalytic activity of metal–organic frameworks (MOFs). Inducing defects through the attachment of functionalized modulators can introduce cooperative units that can tune the bandgap of the material and enhance their chemical, thermal, and photostabilities among other properties. However, the majority of defect engineering studies for photocatalytic applications are limited to Zr-based MOFs, and there is still a lack of interrelation between synthetic variables, the resultant MOF properties, and their effect on their photocatalytic performance. We report a comprehensive study on the defect engineering of the titanium heterometallic MOF M…
Determination of the depth profile distribution of guest species in microporous materials using the voltammetry of immobilized particles methodology:…
2014
A model for determining the in-depth profile distribution of electroactive species hosted in inorganic microporous matrixes using the voltammetry of immobilized particles methodology is described. The method, based on the analysis of cyclic voltammetric data at different potential scan rates, allows us to determine the in-depth profile variation of the concentration of electroactive guest species as well as the evaluation of the (oxidized form)/(reduced form) concentration ratio in cases where two oxidation states of the electroactive species coexist. The application to Maya blue-type materials prepared from lapachol, a naphtoquinonic dye, and palygorskite and kaolinite clays is reported. T…
New heterogeneous catalysts for greener routes in the synthesis of fine chemicals
2007
Abstract New strong Lewis acid SnTf-MCM-41 and SnTf-UVM-7 catalysts with unimodal and bimodal pore systems were prepared in a two-step synthesis in which the triflic acid (Tf) was incorporated to previously synthesized mesoporous tin-containing silicas. The Sn incorporation inside the pore walls was carried out through the Atrane method. The SnTf-UVM-7 catalysts were prepared by aggregating nanometric mesoporous particles defining a hierarchic textural-type additional pore system. Following these procedures, catalysts with different Si/Sn ratios—21.8 to 50.8 for SnTf-MCM-41 and 18.4 for SnTf-UVM-7—were prepared. These new materials were tested in the acylation of aromatic sulfonamides using…
Atmospheric pressure plasma polymerisation of metalloporphyrins containing mesoporous membranes for gas sensing applications
2013
Abstract Metalloporphyrins are embedded in an organosilicon matrix by an easily up-scalable atmospheric pressure dielectric barrier discharge method. The integrity of the metalloporphyrins, followed by UV–visible spectroscopy, is successfully preserved and their aggregation prevented. The single molecule properties, rather than the bulk ones, are thus enhanced. Exposure to triethylamine, which reaches the metalloporphyrins through the pores of the organosilicon membrane, led to a shift in the absorption spectrum and confirms the gas sensing potential of such coatings.
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…