Propriedades fotoluminescentes de PbMoO4 obtidos a partir dos métodos de coprecipitação e processamento hidrotérmico

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Sintesi hidrotermal bidezko titanio dioxidozko nanohodien lorpena

[EUS] Gaur egun nanozientzia zientzia eta teknologia arlo guztietara zabaldu da, gizarte garapenean eragin handia izan du. Ikerkuntza arlo guztietara zabaldu da ezinezkoak ziruditen erronkak argitu eta ezezagunak ditugun ezagutzak garatzeko asmoz. Lan honetan TiO2 nanohagatxoen sintesia burutu da metodo hidrotermala erabiliz. Sintesi baldintzek lortutako produktuaren egituran eta forman duten eragina kontuan harturik, sintesia gertatzeko ezinbestekoak diren pHa, tenperatura eta denbora aztertu dira. Ondoren, tratamendu kimiko eta termiko ezberdinen bidez konposizio eta egitura ezberdinak lor daitezkeela frogatu da. Bereziki, surfaktante eta pHaren arabera egitura ezberdinak lortzen direla ikusirik. Sintetizatutako laginen karakterizazioa burutzeko X izpien difrakzioa, transmisio bidezko mikroskopia elektronikoa, infragorri espektroskopia, eta termograbimetria teknikak erabili dira. Hauen bidez NaTi3O6·(OH)x·(H2O)y , (TiO2)x(H2O)y , anatasa eta rutilo faseak identifikatu dira, eta nanohagatxoen lodiera eta morfologia ezberdinak ikusi dira.

Síntese hidrotermal assistida por micro-ondas como metodologia sintética eficiente para obtenção da rede metalorgânica [ZN(BDC)(H2O)2]n

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Processamento de nanomateriais em hidrotermal convencional e hidrotermal de microondas

Copper, zinc and nickel oxides present different properties in nanostructured form. These nanomaterials present very interesting morphologies such as urchin and flowers. This differents arquitechures can be employed in near future in several areas of applications as: nanocatalysis, nanooptoeletronic and nanomedicine.

Estudo das propriedades microestruturais e ópticas do BaMoO4 processado em hidrotermal assistido por microondas

Pós-graduação em Ciência e Tecnologia de Materiais - FC

Síntese, processamento em hidrotermal convencional/microondas e propriedades fotoluminescentes dos pós de BaW 'O IND. 4'

Pós-graduação em Ciência e Tecnologia de Materiais - FC

Síntese de nanoestruturas de ZnO por redução carbotérmica e hidrotermal, assistido por micro-ondas: caracterização como sensor

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Síntese hidrotermal de sodalita básica a partir de um rejeito de caulim termicamente ativado

Basic sodalite was successfully synthesized by hydrothermal method using kaolin waste as source of Aluminum and Silicon. This waste is mainly composed by kaolinite and is produced in large amount by kaolin processing industries for paper coating from the Amazon region. Initially, the waste has been calcined at 700 ºC for 2 h and then reacted with the following solutions: Na₂CO₃ and mixture of Na₂CO₃ + NaOH to 150 ºC with autogenous pressure for 24 h. The raw materials and transformed materials were characterized by XRD, FTIR and SEM. In both studied media, well-crystallized, basic sodalite was the only phase synthesized, while in the literature usually a mixture of zeolites is obtained.

Síntese de nanocatalisador cerâmico a base de SnO2 pelo método hidrotermal assistido por micro-ondas aplicado a reação de transesterificação do óleo de babaçu

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Caracterização de filmes de BaxSr1-xTiO3 Sintetizados pelo método hidrotermal assistido por micro-ondas e depositados por eletroforese

Pós-graduação em Ciência e Tecnologia de Materiais - FC

Nanopartículas de CeO2 modificadas com Er obtidas pelo método hidrotermal microondas: estudo fotoluminescente

The development of nanostructured materials have aroused great interest of the industries all over the country, since they enable the development of devices that can be used as gate insulators on silicon transistors, electrochromic devices, solid electrolyte oxygen sensors and as a photoluminescent materials . In this project, it is proposed to investigate the optical properties of CeO2 modified with rare earth Er processed in hydrothermal-microwave. The synthesis of one-dimensional nanostructures (1D) was measured from dilute aqueous solutions of acids and salts of starting reagents in the presence of chemical basis, after these aqueous solutions were processed on hydrothermal-microwave to particle growth. The particles obtained after processing were characterized by X-ray Diffraction, Rietveld Analysis and Raman Spectroscopy. The particle morphology was observed by scanning electron microscopy with field emission gun. The synthesis of 1D nanostructures are evaluated for different surfactants and starting precursors (ceria different salts), pH, temperature and pressure which can modify the morphology of the nanostructures. Combining laboratory experiments and theoretical calculations it was desired to understand the organization of the nanoparticles and their resulting structure. Strict control of chemical homogeneity, crystal structure, microstructure and interaction of the CeO2 cluster with different surfactants using the Hartree-Fock method, was intended to obtain properties compatible with their use in catalysts and optical devices. The use of mineralizer agent KOH and 8 minutes of processing time synthesis conditions were chosen to evaluate the effect of Er dopant. It has been proved that this doping with rare earth increases the photoluminescent properties of the compound obtained without change the structural and morphological propreties of ceria

Nanopartículas de CeO2 modificadas com Er obtidas pelo método hidrotermal microondas: estudo fotoluminescente

The development of nanostructured materials have aroused great interest of the industries all over the country, since they enable the development of devices that can be used as gate insulators on silicon transistors, electrochromic devices, solid electrolyte oxygen sensors and as a photoluminescent materials . In this project, it is proposed to investigate the optical properties of CeO2 modified with rare earth Er processed in hydrothermal-microwave. The synthesis of one-dimensional nanostructures (1D) was measured from dilute aqueous solutions of acids and salts of starting reagents in the presence of chemical basis, after these aqueous solutions were processed on hydrothermal-microwave to particle growth. The particles obtained after processing were characterized by X-ray Diffraction, Rietveld Analysis and Raman Spectroscopy. The particle morphology was observed by scanning electron microscopy with field emission gun. The synthesis of 1D nanostructures are evaluated for different surfactants and starting precursors (ceria different salts), pH, temperature and pressure which can modify the morphology of the nanostructures. Combining laboratory experiments and theoretical calculations it was desired to understand the organization of the nanoparticles and their resulting structure. Strict control of chemical homogeneity, crystal structure, microstructure and interaction of the CeO2 cluster with different surfactants using the Hartree-Fock method, was intended to obtain properties compatible with their use in catalysts and optical devices. The use of mineralizer agent KOH and 8 minutes of processing time synthesis conditions were chosen to evaluate the effect of Er dopant. It has been proved that this doping with rare earth increases the photoluminescent properties of the compound obtained without change the structural and morphological propreties of ceria

Síntese e caracterização de pigmentos nanométricos encapsulados pelos métodos dos precursores poliméricos, hidrotermal de microondas e co-precipitação associado à química sol-gel convencional

The demand for materials with high consistency obtained at relatively low temperatures has been leveraging the search for chemical processes substituents of the conventional ceramic method. This paper aims to obtain nanosized pigments encapsulated (core-shell) the basis of TiO2 doped with transition metals (Fe, Co, Ni, Al) through three (3) methods of synthesis: polymeric precursors (Pechini); hydrothermal microwave, and co-precipitation associated with the sol-gel chemistry. The study was motivated by the simplicity, speed and low power consumption characteristic of these methods. Systems costs are affordable because they allow achieving good control of microstructure, combined with high purity, controlled stoichiometric phases and allowing to obtain particles of nanometer size. The physical, chemical, morphological, structural and optical properties of the materials obtained were analyzed using different techniques for materials characterization. The powder pigments were tested in discoloration and degradation using a photoreactor through the solution of Remazol yellow dye gold (NNI), such as filtration, resulting in a separation of solution and the filter pigments available for further UV-Vis measurements . Different calcination temperatures taken after obtaining the post, the different methods were: 400 º C and 1000 º C. Using a fixed concentration of 10% (Fe, Al, Ni, Co) mass relative to the mass of titanium technologically and economically enabling the study. By transmission electron microscopy (TEM) technique was possible to analyze and confirm the structural formation nanosized particles of encapsulated pigment, TiO2 having the diameter of 20 nm to 100 nm, and thickness of coated layer of Fe, Ni and Co between 2 nm and 10 nm. The method of synthesis more efficient has been studied in the work co-precipitation associated with sol-gel chemistry, in which the best results were achieved without the need for the obtainment of powders the calcination process

A new low temperature synthesis route of fraipontite (Zn,Al)3(Si,Al)2O5(OH)4

A low temperature synthesis method based on the decomposition of urea at 90°C in water has been developed to synthesise fraipontite. This material is characterised by a basal reflection 001 at 7.44 Å. The trioctahedral nature of the fraipontite is shown by the presence of a 06l band around 1.54 Å, while a minor band around 1.51 Å indicates some cation ordering between Zn and Al resulting in Al-rich areas with a more dioctahedral nature. TEM and IR indicate that no separate kaolinite phase is present. An increase in the Al content however, did result in the formation of some SiO2 in the form of quartz. Minor impurities of carbonate salts were observed during the synthesis caused by to the formation of CO32- during the decomposition of urea.