Characterization of the Acid Strength of SiO2-ZrO2 Mixed Oxides

n-Butane Isomerization Catalyzed by Sulfated Zirconia Nanocrystals Supported on Silica or γ-Alumina

“…The literature reports on zirconia-alumina [19,20] and zirconia-silica [21][22][23][24][25] mixed oxides in various compositions, and zirconia has been dispersed on alumina [26][27][28][29] and on silica [26,27,[30][31][32][33]. Zirconium has been embedded in the walls of MCM-41 [34][35][36][37] and SBA-15 [38].…”

Highly Dispersed Mixed Zirconia and Hafnia Nanoparticles in a Silica Matrix: First Example of a ZrO2–HfO2–SiO2 Ternary Oxide System

“…It has been in fact demonstrated that an even dispersion of zirconia or hafnia nanoparticles in a silica matrix strongly increases its activity in catalytic reactions such as isopropanol and n-butanol dehydration and cycloesanol dehydrogenation. [63] …”

“…[3][4][5][6][7] The embedding of guest particles in a transparent and dielectric matrix enables fine tailoring of its optical properties, [8] such as refractive index. In the form of powder these mixed oxides are also attracting a growing interest both as catalysts [9][10][11][12][13] as well as catalyst supports. [14] The obtainment of host particles even dispersion in the guest matrix is a requirement to be met in order to get the desired properties.…”

Synthesis of mesoporous ZrO2-SiO2 and WO3/ZrO2-SiO2 solid acids

“…As starting reagents, water solutions of hexafluorosilicic acid (H 2 SiF 6 ) and hexafluorozirconic acid (H 2 ZrF 6 ) [5], tetraethoxysilane, zirconium isopropylate [6,7] and nitrate [8], sodium silicate and zirconium chloride [9] or a zirconium carbonate complex [10] Water sol of oligomers of silicic acid was obtained treating potassium silicate with the cation-exchange resin KU-2 (sulfuretted styrene and divinylbenzene copolymer) [11,12]. In order to synthesize mixed ZrO 2 -SiO 2 oxide, zirconium oxychloride solution in a small amount of water was added to 1 L of polysilicic acid solution (SiO 2 concentration equal 0.4 М) with the mole ratio Zr:Si=1:2 according to [10].…”

“…The synthesis of mixed ZrO 2 -SiO 2 oxide is described in literature [5][6][7][8][9][10], but there is almost no information on the preparation of ternary WO 3 /ZrO 2 -SiO 2 system. As starting reagents, water solutions of hexafluorosilicic acid (H 2 SiF 6 ) and hexafluorozirconic acid (H 2 ZrF 6 ) [5], tetraethoxysilane, zirconium isopropylate [6,7] and nitrate [8], sodium silicate and zirconium chloride [9] or a zirconium carbonate complex [10] Water sol of oligomers of silicic acid was obtained treating potassium silicate with the cation-exchange resin KU-2 (sulfuretted styrene and divinylbenzene copolymer) [11,12].…”