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Synthesis and characterization of thermally stable mesostructured sulfated zirconia by a novel sulfate-assisted alcohothermal route

“…The second weight loss processes between 200 and 500°C are highly exothermic and are assigned to the combustion and continuous decomposition of the covalently anchored ethoxy-groups over the surface of the sample. Similar results have been reported on the zirconia precipitates obtained by thermal decomposition of zirconium alkoxides in organic media [18], where small amounts of alky groups covalently bonded to the surface oxygen atoms of the zirconia particles have been detected. The final weight loss feature centered at 680°C is due to decomposition of SO 2À 4 species on the sample, which leading to the ultimate formation of SO 3 moieties [7].…”

“…Note that the zirconia sample prepared in the absence of ammonium sulfate under otherwise identical conditions shows a type I isotherm, a wide pore size distribution and a low BET surface area of ca. 50 m 2 g À1 [18]. Both pore volumes and pore sizes are much larger for the samples prepared in the presence of ammonium sulfate.…”

“…By coupling alcohothermal and supercritical fluid drying techniques, we have recently demonstrated that it is possible to prepare thermally stable ultrafine zirconia powder with a high surface area (HSA) and welldeveloped textural mesoporosity with a narrow pore size distribution [17,18], the formation of which has been attributed to the facile formation of a robust zirconia alcogel due to the alcohothermal processing. In the present work, we report a novel one-step non-surfactant synthetic route to mesostructured sulfated zirconia materials with a large surface area composed of tetragonal zirconia walls.…”

Synthesis and characterization of mesoporous and nano-crystalline phosphate zirconium oxides

“…1 and 2 show the TG-DTG and TG-DTA profiles of the Zr(OH) 4 , respectively. Three weight loss stages were observed in the temperature range of 25-500 • C. The largest one located between 25 and 200 • C can be attributed to the loss of physically adsorbed water and the evaporation of 1-butanol, this weight loss stage also is related with the first endothermic peak in the DTA profile located at 50 • C [11]. The second stage was highly exothermic (200-350 • C), originating from the combustion of the organic compounds in the sample (alcoxi groups) two peaks located in the DTA profile at 258 and 285 • C [12,13].…”

Highly efficient non-noble metal based nanostructured catalysts for selective CO methanation

“…It is interesting to note that the surface area increased with increasing Ni content. ZN3 showed the highest surface area of 109 m 2 g -1 due to the amorphous nature of ZrO 2 [20]. When the nickel content was increased further, the surface area slightly decreased because of the nickel agglomeration over ZrO 2 (see the increasing NiO crystallite size measured by the XRD analysis).…”