Mixed oxide

About: Mixed oxide is a research topic. Over the lifetime, 5224 publications have been published within this topic receiving 115567 citations.

Spectroscopic Characterization of Sol−Gel-Derived Mixed Oxides

Abstract: Al2O3-, TiO2-, SiO2-, and ZrO2-based mixed-oxide supports were synthesized by sol−gel techniques using 2,4-pentanedione as the complexing/templating agent. These materials have been investigated by employing nitrogen adsorption, 27Al, 29Si, and 1H solid-state magic-angle spinning nuclear magnetic resonance (MAS NMR), diffuse reflectance Fourier transform infrared spectroscopy (DRIFTS), and Fourier transform laser Raman spectroscopy (FT-Raman). Nitrogen adsorption isotherms of the mixed oxides Al2O3−SiO2 and TiO2−SiO2 were of type IV, with hysteresis loops of type I, indicating well-defined pore structure, while other mixed oxides Al2O3−TiO2, Al2O3−ZrO2, TiO2−ZrO2, and ZrO2−SiO2 exhibited type II hysteresis loops, indicating pores of undefined nature. 27Al MAS NMR studies on the alumina-based mixed oxides showed the presence of four-, five-, and six-coordinated aluminum species, the number of four-coordinated framework aluminum sites being highest in the Al2O3−SiO2 mixed oxide. 29Si CP MAS NMR spectra of t...

Synthesis, characterisation and catalytic evaluation of iron–manganese mixed oxide pillared clay for VOC decomposition reaction

Abstract: A series of iron and manganese mixed oxide pillared clay with varying manganese to iron ratio has been successfully synthesized. Prepared materials were characterized by low angle XRD, TG/DTA, hydrogen TPR and nitrogen adsorption desorption experiment. All the materials were found to be thermally stable up to 500 °C having basal spacing ≥16.5 Ǻ. Surface area and pore volume increases with the increase in the metal uptake irrespective of manganese to iron ratio. Catalytic decomposition of acetone and trichloroethylene was studied to find out the suitability of the material for VOC decomposition reaction. Catalyst (S-16/4) having high manganese content acts as better catalyst for the acetone decomposition reaction. Time on stream experiment justifies the stability of the prepared catalyst at least for 20 h with minor change in the activity. However, in case of trichloroethylene (TCE) decomposition catalyst (S-8/12) with higher iron content shows better activity. Quick deactivation of the catalyst for TCE decomposition is noticed for all the prepared materials.

Syngas production from CO2 reforming of methane using Ce-doped Ni-catalysts obtained from hydrotalcites by reconstruction method

Abstract: Ce-doped Ni, Mg and Al hydrotalcites were synthesized through the reconstruction method in the presence of the [Ce(EDTA)] − complex The hydrotalcites and the mixed oxides derived after their thermal decomposition at 500 °C (16 h) were characterized by XRD, TGA-DTA, ICPS, IR, Raman, SEM-EDX, TEM, TPR-H 2 , TPD-CO 2 , XPS and N 2 sorptometry The reconstruction of the mixed oxide is not total in [Ce(EDTA)] − solutions with Ce between 1 and 10%wt The hydrotalcite is reconstructed as hydroxyl-type phase; the reconstruction takes place in the external edges of the oxide granules The complex is deposited, with high distribution, on the external surface of the reconstructed layered structure as species of Ce 4+ and after the calcination generates surface CeO 2 -doped periclase oxides Solids were used in the production of syngas through CO 2 reforming of methane (CH 4 :CO 2 :Ar 5/5/40) using a total fixed flow of 50 mL min −1 and WHSV = 30 L g −1 h −1 between 500 and 800 °C with prior reduction The increase in the Ce load had a promoter effect in catalytic conversions H 2 /CO ratios between 08 and 12 were obtained Ce had a positive effect in the elimination of coke, since a nominal optimal value of 3%wt was obtained