Green synthesis of aminated hyaluronic acid-based silver nanoparticles on modified titanium dioxide surface: Influence of size and chemical composition on their biological properties.

This is the first report on an efficient, "environmentally friendly" chemical reduction method for the synthesis of aminated hyaluronic acid-based silver nanoparticles on the modified surface of titanium dioxide nanoparticles aimed for biological applications. Silver nanoparticles exhibit well-known physical-chemical and optical properties appropriate for different biological applications. Modifying the nanoparticles leads to a change in their expected bioactivity.

Deciphering the role of water and a zinc-doping process in a polyol-based approach for obtaining Zn/Co/Al-based spinels: toward "green" mesoporous inorganic pigments.

Two new families of zinc/cobalt/aluminum-based pigments, with a unique composition, were obtained through the polyol method. The hydrolysis process of a mixture of Co(CHCOO), Zn(acac) and Al(acac) (acac = acetylacetonate ion) in 1,4-butanediol afforded dark blue gels (wPZnxCo1-xAl), in the presence of a supplementary amount of water, and light green powders (PZnxCo1-xAl), respectively, for the water-free procedure ( = 0, 0.2, 0.

Carbon-Coated SiO Composites as Promising Anode Material for Li-Ion Batteries.

Porous silica-based materials are a promising alternative to graphite anodes for Li-ion batteries due to their high theoretical capacity, low discharge potential similar to pure silicon, superior cycling stability compared to silicon, abundance, and environmental friendliness. However, several challenges prevent the practical application of silica anodes, such as low coulombic efficiency and irreversible capacity losses during cycling. The main strategy to tackle the challenges of silica as an anode material has been developed to prepare carbon-coated SiO composites by carbonization in argon atmosphere.

Structural Details of BaTiO Nano-Powders Deduced from the Anisotropic XRD Peak Broadening.

In this study, nano-BaTiO (BTO) powders were obtained via the solvothermal method at different reaction times and were investigated using transmission electron microscopy (TEM), X-ray diffraction (XRD) and Raman spectroscopy. The results were compared with those obtained for a larger crystallite size BTO powder (BTO-m). The sizes of the cuboid crystallites (as determined by XRD and TEM) ranged from about 18 to 24 nm, depending on the reaction time.

Methane Combustion Using Pd Deposited on CeO-MnO/La-AlO Pellistors.

Pd deposited on CeO-MnO/La-AlO has been prepared as a sensitive material for methane (CH) detection. The effect of different amounts (1.25%, 2.

CeO:MnO Catalytic Micro-Converters Tuned for CH Detection Based on Catalytic Combustion under Real Operating Conditions.

Mesoporous CeO:MnO materials (3:7 and 7:3 molar ratio) were prepared by co-precipitation and deposited as porous thick films over alumina (AlO) planar substrate provided with Pt meander. The aim was oriented towards detecting low levels methane (CH) at moderate operating temperatures. Herein we demonstrated that the sensitivity of catalytic micro-converters (CMCs) towards a given peak of CH concentration corresponds to specific gas-surface interaction phenomena.

Undoped SnO as a Support for Ni Species to Boost Oxygen Generation through Alkaline Water Electrolysis.

In this study, the synergistic behavior of Ni species and bimodal mesoporous undoped SnO is investigated in oxygen evolution reactions (OERs) under alkaline conditions without any other modification of the compositional phases or using noble metals. An efficient and environmentally friendly hydrothermal method to prepare bimodal mesoporous undoped SnO with a very high surface area (>130 m g) and a general deposition-precipitation method for the synthesis of well-dispersed Ni species on undoped SnO are reported. The powders were characterized by adsorption-desorption isotherms, TG-DTA, XRD, SEM, TEM, Raman, TPR-H, and XPS.

Bulk Versus Surface Modification of Alumina with Mn and Ce Based Oxides for CH Catalytic Combustion.

This study presents the synthesis and characterization of lanthanum-modified alumina supported cerium-manganese mixed oxides, which were prepared by three different methods (coprecipitation, impregnation and citrate-based sol-gel method) followed by calcination at 500 °C. The physicochemical properties of the synthesized materials were investigated by various characterization techniques, namely: nitrogen adsorption-desorption isotherms, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and H-temperature programmed reduction (TPR). This experimental study demonstrated that the role of the catalytic surface is much more important than the bulk one.

Behavior of Molybdenum⁻Vanadium Mixed Oxides in Selective Oxidation and Disproportionation of Toluene.

This study deals with the behavior of molybdenum⁻vanadium (Mo/V) mixed oxides catalysts in both disproportionation and selective oxidation of toluene. Samples containing different Mo/V ratios were prepared by a modified method using tetradecyltrimethylammonium bromide and acetic acid. The catalysts were characterized using several techniques: nitrogen adsorption⁻desorption isotherms, X-Ray diffraction (XRD), ammonia temperature-programmed desorption (TPD-NH₃), temperature-programmed reduction by hydrogen (H₂-TPR), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, Fourier-transform infrared-spectroscopy (FTIR) and ultraviolet-visible spectroscopies (UV⁻VIS).

Synthesis of Terephthalic Acid by p-Cymene Oxidation using Oxygen: Toward a More Sustainable Production of Bio-Polyethylene Terephthalate.

The synthesis of terephthalic acid from biomass remains an unsolved challenge. In this study, we conducted the selective oxidation of p-cymene (synthesized from biodegradable terpenes, limonene, or eucalyptol) into terephthalic acid over a Mn-Fe mixed-oxide heterogeneous catalyst. The impact of various process parameters (oxidant, temperature, reaction time, catalyst amount, oxygen pressure) on the selectivity to terephthalic acid was evaluated, and some mechanistic aspects were elucidated.

Graphene from Alginate Pyrolysis as a Metal-Free Catalyst for Hydrogenation of Nitro Compounds.

Graphene obtained by pyrolysis of alginate at 900 °C under inert atmosphere and exfoliation is used as a metal-free catalyst for reduction of nitro to amino groups with hydrogen as a reagent. The process is general for aromatic and aliphatic, conjugated and isolated nitro groups, and occurs with low selectivity over hydrogenation of carbon-carbon double bonds.

Graphenes in the absence of metals as carbocatalysts for selective acetylene hydrogenation and alkene hydrogenation.

Catalysis makes possible a chemical reaction by increasing the transformation rate. Hydrogenation of carbon-carbon multiple bonds is one of the most important examples of catalytic reactions. Currently, this type of reaction is carried out in petrochemistry at very large scale, using noble metals such as platinum and palladium or first row transition metals such as nickel.

Heterogeneous gold catalysts for efficient access to functionalized lactones.

A novel class of heterogeneous gold catalysts supported on zeolite beta-NH4+ was prepared by the deposition-precipitation method. This new class of catalyst showed interesting catalytic activities for the intramolecular cycloisomerization of gamma-acetylenic carboxylic acids leading to functionalized gamma-alkylidene gamma-butyrolactones. Analysis of the supported gold species with in situ X-ray photoelectron spectroscopy (in situ XPS) suggests that cationic Au (possibly AuIII) can play an important role in such reactions.