A new method for the synthesis of calcium and magnesium fluorides with high surface areas is proposed; the fluorides obtained by the decomposition of beta-cyclodextrin-metal trifluoroacetate mixtures have surface areas of about 80 and 60 m(2) g(-1) for CaF2 and MgF2, respectively.

UV-shielding property, photocatalytic activity and cytotoxicity (including photocytotoxicity) of citrate-stabilized ceria colloid solutions were studied. It was established that UV-shielding property (namely, the sun protection factor, the critical absorption wavelength and the UVA/UVB-ratio) of ceria nanoparticles are as good as those of titanium dioxide and zinc oxide nanoparticles. It was further demonstrated that ceria nanoparticles possesses substantially lower photocatalytic activity, which additionally decreases upon decrease in ceria particle size. It was found that colloid ceria solutions are non-toxic to mouse fibroblasts (L929) and fibroblast-like cells of African Green monkey (VERO). Moreover, ceria nanoparticles are capable to protect these cells from UV-irradiation-induced damage. It was proposed that nanocrystalline ceria could be used not only as UV-blocking material, but also as prophylactic and even therapeutic compound for sunburns treatment.

Copper- and iron-containing mesoporous silicas were synthesized using beta-cyclodextrin as a template and characterized by XRD, SEM and N(2)-BET techniques; their catalytic activity in phenol monohydroxylation and CO oxidation was demonstrated.

Hydrolysis of metal salts in the presence of hexamethylenetetramine (HMT) is widely used to synthesize a variety of inorganic oxides, including zinc oxide. In particular, this method allows one to obtain ordered arrays of ZnO nanorods [1], which have a high specific surface and low defect content. At present, the ZnO synthesis with the use of HMTA under prehydrothermal conditions has been studied in detail. At the same time no information is available so far regarding the use of this method for the synthesis of ZnO under hydrothermal conditions (at temperatures above 100 °C). We synthesized for the first time zinc oxide with the use of HMT and hydrothermal microwave (HTMW) treatment and analyzed the influence of the synthesis parameters on the morphology and functional properties of zinc oxide.

Synthesis of the nanopowders of CeO2 and ZnO was carried out from the solutions of cerium (III) and zinc salts in the presence of hexamethylenetetramine. The effect of the major synthesis parameters including the molar ratio of the reagents and synthesis temperature on the micromorphology of the formed oxide powders was established. The possibility to vary the size of ZnO and CeO2 nanoparticles under the hydrothermal microwave conditions was demonstrated.

Предложены новые методы получения водных золей нанокристаллического диоксида церия, стабилизированных лимонной и полиакриловой кислотами. Методами просвечивающей электронной микроскопии и УФ-видимой спектроскопии исследована устойчивость золей к гидротермальной обработке в диапазоне температур 120–210°С.

New methods are proposed for preparing aqueous sols of nanocrystalline ceria stabilized by citric or polyacrylic acid. Transmission electron microscopy and UV-Vis spectroscopy were used to study the stability of sols in hydrothermal treatment at temperatures in the range of 120–210°C.

Structure and thermal properties of iron III hydroxide xerogels obtained under high intensity ultrasonic treatment were studied by means of small-angle neutron scattering and heat-flux calorimetry. It was established that sonication affects the mesostructure of amorphous xerogels i.e., increase in their homogeneity, surface fractal dimension, and the sizes of aggregates of primary particles as opposed to the commonly accepted point of view that ultrasonic action cannot lead to notable changes in structure of powders, consisting of nanometer size particles. Ultrasonically induced structural changes in xerogels are evidently confirmed via their notably different reactivity at thermal decomposition under hydrothermal conditions.

The micromorphology and catalytic properties of nanocrystalline TiO 2 /SO 4 2− superacid systems prepared by a conventional sol-gel process, as well as hydrothermal (HT) and microwave-hydrothermal (MW-HT) processes, were analyzed. The samples prepared by the HT process have no developed surfaces and, as a consequence, have no high reactivity in isobutylene oligomerization. The TiO 2 /SO 4 2− samples prepared by single-step MW-HT synthesis in their morphologic, acid, and catalytic properties are competitive with the systems prepared by the conventional multistage sol-gel process.

Hydrolysis of metal salts in the presence of hexa� methylenetetramine (HMTA) is widely used to syn� thesize a variety of inorganic oxides, including zinc oxide. In particular, this method allows one to obtain ordered arrays of ZnO nanorods [1], which have a high specific area and low defect content. At present, the ZnO synthesis with the use of HMTA under prehydro� thermal conditions has been studied in detail. The phase formation has been studied in [2]. The major synthesis parameters, which determine the product micromorphology, were found: the reaction tempera� ture [3], the synthesis duration [4], the molar ratio between the reagents [5, 6], and pH of the reaction medium [7]. At the same time no information has been available so far regarding the use of this method for the synthesis of ZnO under hydrothermal condi� tions (at temperatures above 100 °C). In this connec� tion, in this work, we synthesized for the first time zinc oxide with the use of HMTA and hydrothermal micro� wave (HTMW) treatment and analyzed the influence of the synthesis parameters on the micromorphology and functional properties of zinc oxide synthesized. The starting reagents for the ZnO synthesis were analytical grade Zn(NO3)2 · 6H2O (Aldrich) and C6H12N4 (Fluka). A solution (50 mL) containing zinc nitrate and HMTA with the reagent concentrations of 0.1 mol/L was placed in a Berghof MWS�3* micro� wave digestion system, heated to 105–170°C (heating power of 350–1400 W), and kept at a constant temper� ature for 30 min. Then, the solution was cooled, and the precipitate formed was isolated by centrifugation, washed with distilled water, and dried at 30°C for 24 h. (

Проведено комплексное исследование микроморфологии, физико-химических свойств и фотокаталитической активности порошков нанокристаллического анатаза, формирующихся при гидротермальной обработке растворов сульфата титанила различного состава. Предложена новая методика гидротермального синтеза нанокристаллического анатаза с удельной поверхностью 50 м2/г, обладающего фотокаталитической активностью, существенно превосходящей активность коммерческого препарата Degussa Р25.

We carried out a thorough study of the micromorphology, physicochemical properties, and photocatalytic activity of nanocrystalline anatase powders formed during the hydrothermal treatment of titanyl sulfate solutions of various compositions. A new procedure is proposed for the hydrothermal synthesis of nanocrystalline anatase having specific surface areas of ∼50 m2/g and photocatalytic activities exceeding the activity of the commercially available Degussa P25 formulation.