Photocatalytic reactions to convert CO2 and H2O into solar fuels using only solar irradiation have been investigated in this work. For this purpose, titanosilicate ETS-10 was decorated with Cu2O and CuO nanoparticles and their properties were analyzed by different techniques. The final materials were applied in photoreduction of CO2 in gas phase under 20 h of solar irradiation. In the final, the products oxygen, acetic acid, formaldehyde and methanol were detected by chromatographic techniques. Photoluminescence and electrochemical studies indicate the interaction between CuxO nanoparticles and Ti-O-Ti-O on the surface of ETS-10, corroborating with the results obtained in the photocatalytic experiments. The best CO2 photoconversion efficiencies into methanol were obtained when using ETS-10/CuxO compared to pure ETS-10. Another important finding in this study is the fact that the reactions were carried out in the gas phase and no scavenge donors were employed.

The improvements on aluminosilicates dissolution through microwave-assisted acid decomposition procedures for Na and Al quantification by inductively coupled plasma optical emission spectrometry (ICP OES) are reported here. Complete dissolution of the samples is achieved employing 4 mL of HNO3 and 3-4 mL of HF thus reducing the total amount of these reactants in comparison with procedures found in the literature. Additionally, the type of crucibles used in the calcination for sample preparation step is also evaluated. Na and Al concentrations are in agreement with the expected values on the samples. Estimated silicon amount is achieved by difference of sodium and aluminum, and then Si/Al molar ratios were calculated for samples calcined in both porcelain (Si/Al is in the range 22-42) and platinum (Si/Al is in the range 27-40) crucibles, showing no difference between these procedures.

Muitos estudos recentes estão direcionados à área de produção de nanocompósitos poliolefínicos já que eles melhoram as propriedades dos polímeros em muitas aplicações. O desafio mais importante é a obtenção de uma boa dispersão das cargas de reforço na matriz polimérica. É consenso nos estudos realizados que a dispersão conduzida pela polimerização in situ é a mais eficiente, conferindo ao sistema, adicionalmente, as vantagens da catálise heterogênea. Esta contribuição oferece uma revisão bibliográfica das características das cargas de reforço mais empregadas, de sua utilização como suporte de catalisadores metalocênicos e da aplicação na produção in situ de nanocompósitos.

The production of polyolefin nanocomposites has been the field of many studies for improving polymer properties for many applications. The most important challenge on the area is the preparation of the fillers randomly dispersed on polymer matrix. It is general agreement, however, that the dispersion obtained through in situ polymerization is the most efficient and, additionally, confers to the system the advantages of heterogeneous catalysis. This contribution offer a review of characteristics of the most employed fillers, their use as metallocene catalysts supports and the application on in situ production of nanocomposites.

O objetivo deste trabalho foi produzir e caracterizar partículas lipídicas (MpLs) que possam ser utilizadas como carreadores de altas quantidades de um recheio hidrofílico e avaliar a influência da quantidade de recheio sobre a performance das micropartículas. As MpLs foram produzidas por spray cooling a partir de misturas de ácidos graxos líquidos e sólidos (ácido esteárico e oléico) e gordura vegetal hidrogenada, contendo solução de glucose como recheio e lecitina de soja como surfactante. A performance das MpLs foi avaliada por meio da quantificação do recheio efetivamente encapsulado, da quantidade presente na superfície das MpLs e do perfil de liberação do recheio em meio aquoso. Observações morfológicas mostraram que as MpLs apresentaram forma esférica e superfície enrugada porém contínua, com um tamanho médio entre 25 e 32 µm. A quantidade efetivamente encapsulada foi superior a 78% para todas as formulações avaliadas. Maior quantidade de glucose superficial foi observada nas formulações em que soluções mais concentradas de glucose foram utilizadas, independente da relação lipídio-solução. Os resultados da liberação mostraram que a retenção do recheio foi significativamente influenciada pela concentração de glucose utilizada, enquanto a modulação da liberação foi influenciada pela relação lipídio:solução de glucose.

The objective of this research was to produce and characterize lipid particles (MpLs) that may be used as carriers of high amounts of hydrophilic core and evaluate the influence of the core amount on the performance of lipid microparticles. The MpLs were produced by spray cooling from solid and liquid lipid mixtures (stearic and oleic fatty acids and partly hydrogenated vegetable fat) containing glucose solution as core and soy lecithin as surfactant. The performance of MpLs was evaluated by means of the effective amount of encapsulated core, the core amount present on the surface of MpLs (superficial glucose) and the core release profile in aqueous solution. Morphological observations showed that MpLs presented spherical shape and a rugged and continuous surface, and an average diameter between 25 and 32 µm. The effective amount of encapsulated core was greater than 78% for all formulations evaluated. Larger amounts of superficial glucose were found in formulations in which more concentrated glucose solutions were used, regardless of the glucose lipid-solution ratio. The release results showed that core retention was significantly influenced by the glucose solution concentration, whereas release modulation was influenced by the glucose lipid-solution ratio.

Vanadium-containing molecular sieves are redox catalysts and are good candidates as substitutes for oxide-supported V2O5 in a number of reactions. These materials have the advantage of presenting better dispersion of vanadium species, as well as shape-selective properties and controllable acidities. They may be prepared by one-pot synthesis or by post-synthesis methods and a number of techniques such as diffuse reflectance UV-visible spectroscopy, 51V nuclear magnetic resonance and electron paramagnetic resonance, to name but a few, have been used to characterize these materials. In this review, methods of preparation of vanadium-modified molecular sieves, their characterization and applications in catalysis are discussed.

Este trabalho descreve os métodos de produção e os usos potenciais das peneiras moleculares de carbono. A principal rota sintética para estes materiais é a replicação, onde uma peneira molecular de sílica ou aluminossilicato é usada como gabarito (template) para o crescimento de uma fase carbonácea nos seus canais e cavidades. Estes materiais podem ter aplicações tão variadas como separação, adsorção e armazenamento de gases, como eletrodos em baterias e como suportes de catalisadores, todas elas extremamente dependentes da porosidade da peneira molecular de carbono.

This paper describes the production methods and the prospective uses of carbon molecular sieves. The main route to these materials is replication synthesis, where a silica or aluminosilicate molecular sieve is used as template to grow the carbonaceous phase in the voids. These materials may have applications as varied as in separation, adsorption and storage of gases, as electrodes in batteries, and as catalyst supports, all of them highly dependent on the molecular sieve porosity.

Apresentamos aqui os primeiros resultados que mostram a diferença de estabilidade térmica do complexo (eta6-benzeno)tricarbonilcromo(0), [Cr(eta6-C6H6)(CO) 3], quando ancorado em sítios diferentes dentro das cavidades alfa do zeólito Na56Y, sítios 1 e 2. Quando o sistema é aquecido sob vácuo dinâmico, o complexo ancorado no sitio 1, onde as interações C6H6-Na+ e Na+-OC são mais fortes, decompõe mais rapidamente que o complexo ancorado no sitio 2, onde tais interações são mais fracas. Sob vácuo estático, a velocidade de decomposição do complexo nos dois sítios é quase a mesma. O complexo no interior de Na56Y é menos estável que o mesmo complexo no estado sólido.

We present here the first results that show the different thermal stabilities of the complex (eta6-benzene)tricarbonylchromium(0), [Cr(eta6-C6H6)(CO) 3], when anchored at different sites inside the alpha-cages of zeolite Na56Y, sites 1 and 2. When the system is heated under dynamic vacuum, the complex anchored at site 1, in which the interactions C6H6-Na+ and Na+-OC are stronger, decomposes slower than the complex anchored at site 2, in which such interactions are weaker. When the system is heated under static vacuum, the rates of decomposition of the complex anchored in both sites are comparable. The complex inside Na56Y is less stable than the same complex in the solid state.