Herein, we demonstrate a simple hydrothermal route to synthesizing ZnSe/ZnO type II heterostructure using L-cysteine as a capping agent. The use of nanomaterials in bioimaging and photocatalysis towards the degradation of Azophloxine dye is of potential interest. The synthesized ZnSe/ZnO nanomaterials were characterized by UV-Vis absorption spectroscopy, fluorescence spectroscopy, IR spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy.
View Article and Find Full Text PDFThis paper describes an alternative method for the in situ synthesis of gold nanoparticles (AuNPs) with a particle size of less than 3 nm, using nanoreactors formed by reverse micelles of 1,4-bis-(2-ethylhexyl) sulfosuccinate sodium (AOT) and nanoparticle stabilization with l-cysteine, which favor the preparation of nanoparticles with size and shape control, which are homogeneously dispersed (1% by weight) on the support of titanium dioxide nanowires (TNWs). To study the activity and selectivity of the prepared catalyst (AuNPs@TNWs), an aqueous solution of 40 mM glycerol was irradiated with a green laser (λ = 530 nm, power = 100 mW) in the presence of the catalyst and O as an oxidant at 22 °C for 6 h, obtaining a glycerol conversion of 86% with a selectivity towards hydroxypyruvic acid (HA) of more than 90%. From the control and reactions, we concluded that the Ti-OH groups promote the glycerol adsorption on the nanowires surface and the surface plasmon of the gold nanoparticles favors the selectivity of the reaction towards the hydroxypyruvic acid.
View Article and Find Full Text PDFSupported metal single atom catalysis is a dynamic research area in catalysis science combining the advantages of homogeneous and heterogeneous catalysis. Understanding the interactions between metal single atoms and the support constitutes a challenge facing the development of such catalysts, since these interactions are essential in optimizing the catalytic performance. For conventional carbon supports, two types of surfaces can contribute to single atom stabilization: the basal planes and the prismatic surface; both of which can be decorated by defects and surface oxygen groups.
View Article and Find Full Text PDFPhotodynamic therapy (PDT) has developed as an efficient strategy for cancer treatment. PDT involves the production of reactive oxygen species (ROS) by light irradiation after activating a photosensitizer (PS) in the presence of O. PS-coupled nanomaterials offer additional advantages, as they can merge the effects of PDT with conventional enabling-combined photo-chemotherapeutics effects.
View Article and Find Full Text PDFThe catalytic oxidation of phenethoxybenzene as a lignin model compound with a β-O-4 bond was conducted using the Keggin-type polyoxometalate nanocatalyst (TBA)[PMoVO]. The optimization of the process's operational conditions was carried out using response surface methodology. The statistically significant variables in the process were determined using a fractional factorial design.
View Article and Find Full Text PDFThis communication proposes a preliminary simplified kinetic model for the hydrogenation of 1-phenyl-1,2-propanedione that can render up to eight compounds, involving regioselectivity and enantioselectivity. The catalytic system comprises two functionalities; the heterogeneous catalyst (Ir/TiO) plays the role for the hydrogenation, whereas the adsorption/binding to the active site is played by a chiral molecule (cinchonidine), added to the reaction mixture. The reaction occurs at room temperature and total pressure of 40 bar.
View Article and Find Full Text PDFEnviron Sci Pollut Res Int
December 2023
In the present work, halloysite nanotubes modified with gold nanoparticles (AuNPs-HNT) are successfully prepared by wet chemical method for the catalytic degradation of phenothiazine dyes (azure B (AZB) and toluidine blue O (TBO)) and also cleaner reduction of 4-(4-nitrophenyl)morpholine (4NM) in the sodium borohydride (NaBH) media. The catalyst is formulated by modifying the HNT support with a 0.964% metal loading using the HNT supports modified with 3-aminopropyl-trimethoxysilane (APTMS) coupling agent to facilitate the anchoring sites to trap the AuNPs and to prevent their agglomeration/aggregation.
View Article and Find Full Text PDFE-selectin is a cell-adhesion receptor with specific recognition capacity toward sialo-fucosylated Lewis carbohydrates present in leukocytes and tumor cells. E-selectin interactions mediate the progress of inflammatory processes and tumor metastasis, which aroused the interest in using this protein as a biomolecular target to design glycomimetic inhibitors for active targeting or therapeutic purposes. In this work, we report the rational discovery of two novel glycomimetic peptides targeting E-selectin based on mutations of the reference selectin-binding peptide IELLQAR.
View Article and Find Full Text PDFNanoscale molecularly imprinted polymers (nanoMIPs) are powerful molecular recognition tools with broad applications in the diagnosis, prognosis, and treatment of complex diseases. In this work, fully atomistic molecular dynamics (MD) simulations are used to assist the design of nanoMIPs with recognition capacity toward l-fucose and d-mannose as prototype disease biomarkers. MD simulations were conducted on prepolymerization mixtures containing different molar ratios of the monomers -isopropylacrylamide (NIPAM), methacrylamide (MAM), and (4-acrylamidophenyl)(amino)methaniminium acetate (AB) and fixed molar ratios of the cross-linker ethylene glycol dimethacrylate (EGDMA) in explicit acetonitrile as the porogenic solvent.
View Article and Find Full Text PDFA simple, colorimetric and visual method is described for the determination of cysteamine (CA) using polyvinylpyrrolidone-stabilized silver nanoparticles (PVP-AgNPs) as a colorimetric probe. The sensing method was based on the aggregation of PVP-AgNPs that led to the changes in the color and absorption profile of the probe. The aggregation of PVP-AgNPs in the presence of CA was evidenced by using transmission electron microscopy (TEM), zeta and dynamic light scattering (DLS) measurements.
View Article and Find Full Text PDFIn this work, Au nanoparticles, supported in AlO nanowires (ANW) modified with (3-aminopropyl)trimethoxysilane were synthetized, for their use as catalysts in the hydrogenation reaction of 4-(2-fluoro-4-nitrophenyl)-morpholine and 4-(4-nitrophenyl)morpholin-3-one. ANW was obtained by hydrothermal techniques and the metal was incorporated by the reduction of the precursor with NaBH posterior to superficial modification. The catalysts were prepared at different metal loadings and were characterized by different techniques.
View Article and Find Full Text PDFThe effect of the ZrO loading was studied on spherical SiO@ZrO-CaO structures synthetized by a simple route that combines the Stöber and sol-gel methods. The texture of these materials was determined using S by N adsorption, where the increment in SiO spheres' surface areas was reached with the incorporation of ZrO. Combined the characterization techniques of using different alcoholic dissolutions of zirconium (VI) butoxide 0.
View Article and Find Full Text PDFMaterials (Basel)
November 2019
The effect of a second porous SiO shell in the activity and selectivity of the FeO@SiO-Pt catalyst in the hydrodenitrogenation of indole is reported. The double FeO@SiO-Pt@SiO structure was prepared by coating FeO nanoparticles with tetraethyl orthosilicate (TEOS) with a further impregnation of 1.0 wt.
View Article and Find Full Text PDFPalladium N,N'-bis(3-allylsalicylidene)o-phenylenediamine complex (PdAS) immobilized onto mesoporous polymeric methyl acrylate (MA) based resins (PdAS(x)-MA, x = 1, 2, 5, or 10 wt.%) were successfully prepared as heterogeneous catalysts for the Heck reaction. The catalysts were synthesized via radical suspension polymerization using PdAS as a metal chelate monomer, divinylbenzene and MA as co-monomers.
View Article and Find Full Text PDFThe type of metal oxide affects the activity and selectivity of Fe₂O₃⁻SiO₂⁻MeO₂⁻Pt (Me = Ti, Sn, Ce) catalysts on the hydrogenation of cinnamaldehyde. The double shell structure design is thought to protect the magnetic Fe₂O₃ cores, and also act as a platform for depositing a second shell of TiO₂, SnO₂ or CeO₂ metal oxide. To obtain a homogeneous metallic dispersion, the incorporation of 5 wt % of Pt was carried out over Fe₂O₃⁻SiO₂⁻MeO₂ (Me = Ti, Sn, Ce) structures modified with (3-aminopropyl)triethoxysilane by successive impregnation-reduction cycles.
View Article and Find Full Text PDFMater Sci Eng C Mater Biol Appl
August 2016
PAMAM-grafted TiO2 nanotubes (PAMAM-TiO2NT) have been synthesized and evaluated as new drug nanocarriers, using curcumin (CUR), methotrexate (MTX), and silibinin (SIL) as model therapeutic compounds. TiO2NT were surface-modified using a silane coupling agent and subsequently conjugated with PAMAM dendrimer of the third generation. The characterization of PAMAM-TiO2NT nanomaterials was performed by FTIR, TEM, N2 adsorption-desorption isotherms, XRD, and TGA techniques, which accounted for a 2.
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