処理中

しばらくお待ちください...

設定

設定

出願の表示

1. CA2781794 - COMPLEX OXIDE, METHOD FOR PRODUCING SAME AND EXHAUST GAS PURIFYING CATALYST

注意: このテキストは、OCR 処理によってテキスト化されたものです。法的な用途には PDF 版をご利用ください。

[ EN ]
The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:
1. A silicon-containing cerium composite oxide consisting of cerium, silicon, and oxygen, with a content of said silicon being 2 to 20 mass% in terms of SiO2, said composite oxide being produced by a method comprising the steps of: (a) providing a cerium solution at least 90 mol% of which cerium ions are tetravalent, wherein said cerium solution is a ceric nitrate solution or an ammonium ceric nitrate solution, (b) heating said cerium solution at 60 °C or more for a duration of 10 minutes to 48 hours to obtain a cerium suspension, (c) adding a precipitant to said cerium suspension to obtain a precipitate, (d) calcining said precipitate at 250 to 500 °C for a duration of 30 minutes to 36 hours to obtain a cerium oxide, (e) impregnating said cerium oxide with a solution of a silicon oxide precursor, and (f) calcining said cerium oxide impregnated with said solution of said silicon oxide precursor at 300 to 700 °C for a duration of 1 to 10 hours, wherein said composite oxide has a specific surface area of at least 40 m2/g as measured by BET method after calcination at 1000 °C for 5 hours, and a reducibility represented by a percent of trivalent cerium in the composite oxide reduced from tetravalent cerium of at least 30 % as calculated from measurement of temperature-
programmed reduction from 50 °C to 900 °C after calcination at 1000 °C for 5 hours.
2. A silicon-containing cerium composite oxide consisting of cerium, silicon, and oxygen, with a content of said silicon being 2 to 20 mass% in terms of SiO2, said composite oxide being produced by a method comprising the steps of: (A) providing a cerium solution at least 90 mol% of which cerium ions are tetravalent, wherein said cerium solution is a ceric nitrate solution or an ammonium ceric nitrate solution, (B) heating said cerium solution at 60 °C or more for a duration of 10 minutes to 48 hours to obtain a cerium suspension, (C) adding a silicon oxide precursor to said cerium suspension, (D) heating said cerium suspension containing said silicon oxide precursor at 100 °C or more for a duration of minutes to 6 hours, (E) adding a precipitant to said cerium suspension containing said silicon oxide precursor heated in step (D) to obtain a precipitate, and (F) calcining said precipitate at 300 to 700 °C for a duration of 1 to 48 hours, wherein said composite oxide has a specific surface area of at least 40 m2/g as measured by BET method after calcination at 1000 °C for 5 hours, and a reducibility represented by a percent of trivalent cerium in the composite oxide reduced from tetravalent cerium of at least 30 % as calculated from measurement of temperature-
programmed reduction from 50 00 to 900 °C after calcination at 1000 00 for 5 hours.
3. The silicon-containing cerium composite oxide according to claim 1 or 2, wherein said composite oxide has a specific surface area of at least 60 m2/g as measured by BET method after calcination at 900 °C for 5 hours.
4. The silicon-containing cerium composite oxide according to any one of claims 1 to 3, wherein said composite oxide has a reducibility represented by a percent of trivalent cerium in the composite oxide reduced from tetravalent cerium of at least 35 % as calculated from measurement of temperature-programmed reduction from 50 00 to 900 °C after calcination at 1000 00 for 5 hours.
5. The silicon-containing cerium composite oxide according to any one of claims 1 to 4 with a content of said silicon being 5 to 20 mass% in terms of SiO2.
6. A method for producing a silicon-containing cerium composite oxide comprising the steps of: (a) providing a cerium solution at least 90 mol% of which cerium ions are tetravalent, wherein said cerium solution is a ceric nitrate solution or an ammonium ceric nitrate solution, (b) heating said cerium solution at 60 °C or more for a duration of 10 minutes to 48 hours to obtain a cerium suspension, (c) adding a precipitant to said cerium suspension to obtain a precipitate,
(d) calcining said precipitate at 250 to 500 00 for a duration of 30 minutes to 36 hours to obtain a cerium oxide, (e) impregnating said cerium oxide with a solution of a silicon oxide precursor, and (f) calcining said cerium oxide impregnated with said solution of said silicon oxide precursor at 300 to 700 °C for a duration of 1 to 10 hours.
7. A method for producing a silicon-containing cerium composite oxide comprising the steps of: (A) providing a cerium solution at least 90 mol% of which cerium ions are tetravalent, wherein said cerium solution is a ceric nitrate solution or an ammonium ceric nitrate solution, (B) heating said cerium solution at 60 00 or more for a duration of 10 minutes to 48 hours to obtain a cerium suspension, (C) adding a silicon oxide precursor to said cerium suspension, (D) heating said cerium suspension containing said silicon oxide precursor at 100 °C or more for a duration of minutes to 6 hours, (E) adding a precipitant to the cerium suspension containing the silicon oxide precursor heated in step (D) to obtain a precipitate, and (F) calcining the precipitate at 300 to 700 00 for a duration of 1 to 48 hours.
8. The method according to claim 6 or /, wherein a cerium content of the cerium solution in step (a) or (A) is 5 to 100 g/L in terms of CeO2.
9. A catalyst for exhaust gas purification comprising a silicon-containing cerium composite oxide as defined in any one of claims 1 to 5.