Idalia Gómez de la Fuente

Review: Graphene-supported coordination complexes and organometallics: properties and applications

Abstract Recent advances in the functionalization of graphene (G) and graphene oxide (GO) using classical coordination complexes, as well as σ- and π-organometallic compounds as precursors, are discussed. Graphene can form hybrids via covalent or non-covalent interactions with metal complexes of carboxylates, amines, polypyridine compounds, a host of N,O-containing ligands, porphyrins, phthalocyanines, carbonyls, cyclopentadienyls, pyrene-containing moieties, and other aromatic structures. The hybrid constructs are interesting for applications in catalysis, energy storage, and corrosion inhibition and present interesting possibilities of modulating the electronic structure of graphene.

State of the art of nanoforest structures and their applications

Forest-like nanostructures, their syntheses, properties, and applications are reviewed. Nanoforests are mainly represented by carbon nanotubes, zinc and titanium oxides, and gold, and much less frequently by other metals, metal oxides, arsenides and phosphides. These nanostructures generally consist of more simple 1D objects, such as nanowires, nanopillars, nanorods, nanotrees, nanofibers or nanotubes. Synthesis methods for nanoforests vary from catalytic pyrolysis or thermal decomposition of hydrocarbons to electrophoretic deposition, hydrothermal routes, electron beam lithography, focused-ion-beam techniques, vapor phase transport, facet-selective etching and pulsed deep reactive etching technologies, among others. A number of applications for the forest-like nanostructures are generalized, for instance as sensors/detectors, photoanodes in solar and fuel cells, supercapacitors and energy storage devices, in SERS applications, optical and MEMs switching devices, water splitting processes, CO2 fixation, and as supports or targets for biomolecules. In general, it is expected that more varieties of compounds and materials with exciting properties can be obtained in this form in the near future, thus expanding numerous applications of forest-like nanostructures.

Decoration of Carbon Nanotubes With Metal Nanoparticles: Recent Trends

Modern methods for external decoration of carbon nanotubes (CNTs) with elemental metal nanoparticles are reviewed. Carbon nanotubes can be decorated by indirect and direct physicochemical and physical methods mainly with noble and transition metals. The fabricated nanocomposites possess a series of useful applications in the fields of fuel cells, chemo/biosensors, solar cells, drug delivery, catalysis, and hydrogen storage. The first principal calculations and other related theoretical studies on these metal-CNTs nanohybrids are discussed.

Iron-based Nanomaterials in the Catalysis

Available data on catalytic applications of the iron-containing nanomaterials are reviewed. Main synthesis methods of nZVI, nano-sized iron oxides and hydroxides, core-shell and alloy structures, ferrites, iron-containing supported forms, and composites are described. Supported structures include those coated and on the basis of polymers or inert inorganic materials (i.e., carbon, titania or silica). Description of catalytic processes includes the decomposition reactions (in particular photocatalytic processes), reactions of dehydrogenation, oxidation, alkylation, C–C coupling, among a series of other processes. Certain attention is paid to magnetic recovery of catalysts from reaction systems and their reuse up to several runs almost without loss of

Less-Common Methods of the “Direct Synthesis” Area

Abstract In this chapter, we describe several methods that are common for other types of reactions, but are rare in the synthesis of coordination and organometallic compounds. Certain attention is paid to micrometer-size Rieke metals, a very popular research field before the nanotechnology era. Other methods include the ultrasonic treatment, intercalation, laser ablation sputtering, use of ammonia in distinct forms, and the oxidative dissolution of elemental metals in non-aqueous media. It is concluded that the majority of these techniques, widely used in the decade 1980–1990, have been forgotten, although their further use could lead to novel coordination compounds, which are unavailable by classic chemical routes.

Adsorption of asphaltenes on mixed oxide synthesized by auto-combustion method

Abstract The oil classified as heavy is the one with the largest number of deposits at present. However, these deposits are usually difficult to exploit since they contain a high concentration of asphaltenes which cause problems in the refineries at the time of extraction. Different strategies were used to decrease the effects of asphaltenes, being the most effective the use of adsorbents based on metal oxides. This is because metal oxides prevent the re-precipitation of asphaltenes under oil extraction; these methods can be easy implemented in modern refineries. In this work, we propose the synthesis of mixed oxide (Ni(3/2)xFe2-xO4) by self-combustion technique, being then used as an effective asphaltene adsorbent. Its asphaltene adsorption capacity was compared with nickel oxide and hematite, which were synthesized by controlled precipitation. The oxides were characterized by the techniques of X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR); their morphological characterization was carried out by scanning electron microscopy (SEM). The capacity of adsorption of asphaltenes was determined with the technique of UV-Vis spectroscopy. The results show that the Ni(3/2)xFe2-xO4 is a good adsorbent being compared with hematite and nickel oxide, both for asphaltenes with ether and amino groups. The mixed oxide shows a mayor affinity to asphaltenes containing amino groups, being compared with the hematite and nickel oxide; in addition, the mixed oxide has a low affinity to petroleum, which makes it selective to asphaltenes. Graphical Abstract