Влияние соотношения компонентов в наноразмерной порошковой системе ZrO2-Al2O3 на адсорбцию тестовых красителей

Powders n ZrO2 - (100-n) Al2O3, where n = 0, 35, 65, 100 mol %, were synthesized by the sol-gel hydrolysis method in the presence of a polyvinylpyrrolidon additive, followed by procedure of drying at 180 0C and calcination at 5000C. A complex of physico-chemical methods (low-temperature nitrogen adsorption, diffractometry, IR spectroscopy, electron scanning microscopy with energy dispersion analysis, spectro photometry) allowed us to determine the effect of the composition on the texture, morphology, particle size, porosity, crystallinity and adsorption capacity of mono - and bicomponent oxides. It was found that with an increase in the content of zirconium dioxide, the specific surface area decreases, the average sizes of individual particles and pores increase. The 100% Al2O3 sample has a surface of 176 m2/g and pores of 6 nm in diameter, and the 100% ZrO2 sample has 76 m2/g and 16 nm. In two-component nanoscale powders, these values are intermediate, while in contrast to single-component systems, mutual inhibition of the transition from the amorphous to the crystalline state of the nanopowder is observed. The possibility of using these materials as sorbents of organic substances was tested on the example of anionic (methyl orange) and cationic (methylene blue) dyes. The values of specific methyl orange adsorption ГS (mol/m2) and Henry constants increase with an increase in the ZrO2 content.Гидролизным золь-гель методом в присутствии добавки поливинилпирролидона были синтезированы порошки nZrO2-(100-n) Al2O3, где n = 0, 35, 65, 100 мольных %, с последующими процедурами сушки при 180 0С и прокаливания при 5000С. Комплекс физико-химических методов исследования (низкотемпературная адсорбция азота, дифрактометрия, ИК-спектроскопия, электронная сканирующая микроскопия с энергодисперсионным анализом, спектрофотометрия) позволил определить влияние состава на текстуру, морфологию, размер частиц, пористость, кристалличность и адсорбционную способность моно- и бикомпонентных оксидов. Установлено, что с ростом содержания диоксида циркония удельная поверхность уменьшается, средние размеры индивидуальных частиц и пор увеличиваются. Образец 100% Al2O3 имеет поверхность 176 м2/ги поры 6 нм в диаметре, а образец 100% ZrO2 - 76 м2/г и 16 нм. В двухкомпонентных наноразмерных порошках эти значения промежуточные, при этом в отличие от однокомпонентных систем наблюдается взаимное ингибирование перехода от аморфного к кристаллическому состоянию нанопорошка. Проверена возможность использования данных материалов в качестве сорбентов органических веществ на примере анионного (метиловый оранжевый) и катионного (метиленовый синий) красителей. Значения удельной адсорбции ГS (моль/м2) и констант Генри возрастают с увеличением содержания ZrO2

Effect of composition and calcination temperature of ceria-zirconia-alumina mixed oxides on catalytic performances of ethanol conversion

In the present study, we investigated the effect of preparation method, phase composition and calcination temperature of the (Ce-TZP) - Al2O3 mixed oxides on their structural features and catalytic performance in ethanol conversion. Ceria-zirconia-alumina mixed oxides with different (Ce+Zr)/Al atomic ratios were prepared via sol-gel method. Catalytic activity and selectivity were investigated for ethanol conversion to acetaldehyde, ethylene and diethyl ether. © Published under licence by IOP Publishing Ltd

Ethanol dehydrogenation on copper catalysts with ytterbium stabilized tetragonal ZrO2 support

The physicochemical and catalytic properties of Cu-containing crystalline zirconia, obtained via sol–gel synthesis in the presence of Yb3+ ions and polyvinylpyrrolidone, are studied. DTG/DSC, TEM, XRD and BET methods are used to analyze the crystallization, texture, phase uniformity, surface and porosity of ZrO2 nanopowders. It is shown that increasing the copper content (1, 3, and 5 wt % from ZrO2) raises the dehydrogenation activity in the temperature range of 100–400°C and lowers the activation energy of acetaldehyde formation. It is found that the activity of all Cu/t-ZrO2 catalysts grows under the effects of the reaction medium, due to the migration and redispersion of copper. © 2016, Pleiades Publishing, Ltd

Ethanol dehydrogenation on copper catalysts with ytterbium stabilized tetragonal ZrO2 support

The physicochemical and catalytic properties of Cu-containing crystalline zirconia, obtained via sol–gel synthesis in the presence of Yb3+ ions and polyvinylpyrrolidone, are studied. DTG/DSC, TEM, XRD and BET methods are used to analyze the crystallization, texture, phase uniformity, surface and porosity of ZrO2 nanopowders. It is shown that increasing the copper content (1, 3, and 5 wt % from ZrO2) raises the dehydrogenation activity in the temperature range of 100–400°C and lowers the activation energy of acetaldehyde formation. It is found that the activity of all Cu/t-ZrO2 catalysts grows under the effects of the reaction medium, due to the migration and redispersion of copper. © 2016, Pleiades Publishing, Ltd

Effect of composition and calcination temperature of ceria-zirconia-alumina mixed oxides on catalytic performances of ethanol conversion

In the present study, we investigated the effect of preparation method, phase composition and calcination temperature of the (Ce-TZP) - Al2O3 mixed oxides on their structural features and catalytic performance in ethanol conversion. Ceria-zirconia-alumina mixed oxides with different (Ce+Zr)/Al atomic ratios were prepared via sol-gel method. Catalytic activity and selectivity were investigated for ethanol conversion to acetaldehyde, ethylene and diethyl ether. © Published under licence by IOP Publishing Ltd