The development of novel materials is a fundamental focal point of chemical research; and this interest is mandated by advancements in all areas of industry and technology. A good example of the synergism between scientific discovery and technological development is the electronics industry, where discoveries of new semiconducting materials resulted in the evolution from vacuum tubes to diodes and transistors, and eventually to miniature chips. The progression of this technology led to the development * To whom correspondence should be addressed. B.L.C.: (504) 2801385 (phone); (504) 280-3185 (fax); bcushing@uno.edu (e-mail). C.J.O.: (504)280-6846(phone);(504)280-3185(fax);coconnor@uno.edu (e-mail). 3893 Chem. Rev. 2004, 104, 3893−3946

http://depa.fquim.unam.mx/amyd//archivero/FidelmarLechugaSanabria_4940.pdf

Recent advances in the liquid-phase syntheses of inorganic nanoparticles.

Using sonochemistry for the fabrication of nanomaterials.

3.2. Preparation 4090 3.3. Intermediate Layers 4090 3.4. Support 4090 3.5. Modification 4091 3.5.1. Silica Membrane Modification 4091 3.5.2. Membrane Structure Modification 4092 3.6. Operational Stability 4092 4. Zeolite Membranes 4092 4.1. Membrane Growth Methods 4093 4.2. Permeation and Gas Transport 4093 4.3. Defect Site Diffusion/Nonzeolitic Pores 4094 4.4. Thin Films 4094 4.5. Zeolite Membrane Modification 4094 4.6. CO2 Sequestration in H2 Separations 4095 4.7. Manufacturing 4095 5. Carbon-Based Membranes 4096 5.1. Carbon Membrane Preparations 4097 5.2. Carbon Membrane Post-treatment 4097 5.3. Carbon Membrane Module Construction 4097 5.4. Selective Surface Flow Membranes 4097 5.5. Disadvantages of Carbon Membranes 4098 5.6. Molecular Sieving Carbon Membranes 4098 5.7. Carbon Nanotubes 4099 6. Polymer Membranes for H2 Separations 4100 6.1. Dense Polymeric Membranes 4100 6.2. Hydrogen Selective Polymeric Membranes 4101 6.3. H2 versus CO2 Selective Polymeric Membranes 4103

Membranes for hydrogen separation.

Colloidal inorganic nanocrystals stand out as an important class of advanced nanomaterials owing to the flexibility with which their physical-chemical properties can be controlled through size, shape, and compositional engineering in the synthesis stage and the versatility with which they can be implemented into technological applications in fields as diverse as optoelectronics, energy conversion/production, catalysis, and biomedicine. The use of microwave irradiation as a non-classical energy source has become increasingly popular in the preparation of nanocrystals (which generally involves complex and time-consuming processing of molecular precursors in the presence of solvents, ligands and/or surfactants at elevated temperatures). Similar to its now widespread use in organic chemistry, the efficiency of "microwave flash heating" in dramatically reducing overall processing times is one of the main advantages associated with this technique. This Review illustrates microwave-assisted methods that have been developed to synthesize colloidal inorganic nanocrystals and critically evaluates the specific roles that microwave irradiation may play in the formation of these nanomaterials.

Microwave-assisted synthesis of colloidal inorganic nanocrystals.

Raman scattering spectroscopy has been used for the characterization of zinc oxide nanoparticles obtained by mechanical activation in a high-energy vibro-mill and planetary ball mill. Raman modes observed in spectra of nonactivated sample are assigned to Raman spectra of the ZnO monocrystal, while the spectra of mechanically activated samples point out to the structural and stoichiometric changes, depending on the milling time and the choice of equipment. Observed redshift and peak broadening of the E2high and E1 (LO) first-order Raman modes are attributed to increased disorder induced by mechanical milling, followed by the effects of phonon confinement due to correlation length decrease. The additional modes identified in Raman spectra of activated ZnO samples are related to the surface optical phonon modes, due to the intrinsic surface defects and presence of ZrO2as extrinsic defects introduced by milling in zirconia vials. Copyright © 2009 John Wiley & Sons, Ltd.

Raman study of structural disorder in ZnO nanopowders

Polymer-stabilized tetragonal ZrO2 nanopowders with average size of ca. 2.0 nm have been prepared by microwave heating in an aqueous solution containing Zr(NO3)4·5H2O, PVA, and NaOH. The photoluminescence of the synthesized ZrO2 fine particles has been investigated.

Photoluminescence of Tetragonal ZrO2 Nanoparticles Synthesized by Microwave Irradiation

Characterization and synthesis of pure ZrO2 nanopowders via sonochemical method

Five methods for the preparation of stabilized ZrO_2 nano-powders have been used. They are hydro-thermal method, (alcohol-thermal) method, sol-gel method, microwave-irradiation, and sonochemical method. XRD (X-ray diffraction) and PL spectra (Photoluminescence spectra) have been utilized to characterize these samples. Stable tetragonal nanometre ZrO_2 powders have been synthesized by these methods. From the XRD pattern, it is clear that the ZrO_2 samples we obtained are crystal and distributed well. The PL pattern shows that the nano-ZrO_2 powders can emit clear red and blue light when they are excited by the ultraviolet. The (emphasis) of this thesis is to discuss the ZrO_2 emission nanocrystals` luminescent procedures.

Fuli Li

Papers

Photoluminescence of Tetragonal ZrO2 Nanoparticles Synthesized by Microwave Irradiation

Characterization and synthesis of pure ZrO2 nanopowders via sonochemical method

Photoluminescence of tetragonal ZrO2 nanoparticles synthesized by severral methods