Thermal Decomposition, Organic-Inorganic Complex in Solid Catalyst Preparation

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We have investigated organic-inorganic complexes for solid catalyst precursors. Thermal decomposition of the Complex is examined in various kinds of solid catalyst. We have found significant results in the use of organic-inorganic complex precursors. (1) Supported-metal catalysts such as Ni-MgO, Ni-SiO_2, and Cu-SiO_2, are prepared using citric acid and poly(ethylene oxide). The use of organic compounds heightens dispersion of metal species on the oxide supports. Also, the organic compounds effectively work as pore-regulating reagents. We can control the size in mesopores of the samples. In addition, we obtained significant diffusion coefficient data of metal ions in liquid phase in the mesopores. It is valuable for evaluating time needed for absorption and washing in the preparation process. (2) Oxides such as silica and titania with high surface area and controlled pore size are prepared using carboxylic acid. The model of pore formation has been discussed : the organic compounds work as pore-regulating reagents in different mechanisms. The former works as simple template, and the latter works as an obstacle for sintering during calcination. (3) Phase separation, induced by spinodal decomposition using organic polymer and silicate species, is adopted for the preparation of oxides such as silica, silica-zirconia, and silica-alumina with bimodal pore structure, which contains mesopores and macropores.