Thermostable yttria-doped inorganic oxide catalyst supports for high temperature reactions

“Petroleum Gas Oil−Ethanol” Blends Used as Feeds: Increased Production of Ethylene and Propylene over Catalytic Steam-Cracking (CSC) Hybrid Catalysts. Different Behavior of Methanol in Blends with Petroleum Gas Oil

“…The yttria-stabilized alumina aerogel was prepared using a sol−gel procedure that was similar to those reported elsewhere. , After activation at 750 °C for 3 h, the solid material (called herein Y−AS) showed the following (approximate) chemical composition: 10 wt % Y 2 O 3 , with the balance being Al 2 O 3 . Its surface does not show any acidity…”

La-Doped Alumina, Lanthanum Aluminate, Lanthanum Hexaaluminate, and Related Compounds: A Review Covering Synthesis, Structure, and Practical Importance

“…When structural changes to the starting alumina are avoided, the doped product will have properties (e.g., pore size distributions) similar to the alumina from which it was obtained. 96 Apart from impregnation, 22,27,28,32,33,51,52,55,61,69,73,77,78,81,85, 89,100,104−112 other doping methods include deposition by precipitation, 78,107 hydrothermal treatment, 91 coprecipitation, 26,83,113 sol−gel synthesis, 34,52,53,58,63,64,66,76,79,93,98,106,114 combustion synthesis, 8 nitrate decomposition, 76 and other solvent-free or solid-state reactions. 16,52,76,94 However, it appears to be difficult to achieve an adequate dispersion of lanthanum on alumina by solid-state reactions.…”

“…In the past, many studies have aimed at improving the thermal stability of aluminas by using new preparation methods or through the addition of dopants. ,,− Such additives exert an influence on the kinetics of sintering and phase transformation . Ca 2+ , Sr 2+ , Ba 2+ , Sn 4+ , Y 3+ , Zr 4+ , La 3+ , Er 3+ , Th 4+ , and other rare earth (RE) ions inhibit the transformation of t-aluminas into the α-phase; Mg 2+ , Ga 3+ , and In 3+ have the opposite effect. − , ,, , − , , − The cation size seems to have a major influence on the effectiveness of dopants. , Figure shows the specific surface areas at 1200 °C for an alumina powder doped with various elements. The corresponding surface area of the undoped alumina was 8–12 m 2 /g, while those of the modified aluminas are ≥40 m 2 /g …”

“…Apart from impregnation, , , ,, , ,, , ,, , , , , , ​ , ​ , ​ − other doping methods include deposition by precipitation, , hydrothermal treatment, coprecipitation, ,, sol–gel synthesis, , , , , , , , , ,, , , combustion synthesis, nitrate decomposition, and other solvent-free or solid-state reactions. , , , However, it appears to be difficult to achieve an adequate dispersion of lanthanum on alumina by solid-state reactions. E.g., Huang et al observed no stabilizing effect (at 1200 °C) for samples prepared by calcination of mechanically mixed boehmite and LaAlO 3 or La 2 O 3 .…”

Étude mécanistique et structurale des résines R/F

“…Elle met en jeu des re ´actions chimiques douces et ouvrant la voie a `des applications originales. Ce proce ´de ´a e ´te ´utilise ´pour synthe ´tiser des gels, a `partir des oxydes me ´talliques [4][5][6], donnant des solides finement divise ´et aussi transparents [7][8][9]. Ils sont connus sous le nom de xe ´rogels, ae ´rogels, cansogel et cryogel selon la me ´thode de se ´chage utilise ´e [10][11][12][13][14][15] basique [10,16].…”