Preparation,Characterization Of Supported-type Platinum Catalysts And Study Of Its Catalytic Activities

The thesis contains two parts: â‘  the preparation , characterization of supported-type platinum catalysts and study of the activity assays of hydrogen and dehydrogen-cyclization; â‘¡the activity investigation of CoCr, ZnCr series of hydrotalcites derived composite oxides.Metal platinum, an important rearranged catalyst, has been extensively applied in the catalyst industry, especially in the petroleum and chemistry industry. So in the first part a series of Pt-containing mono-metal and Pt-Re-containing bi-metal supported-type catalysts via bond linkage-saturated method with the carrier Y -Al2O3 were synthesized. The carrier was modified with r -GOPS in advance.The interaction between r -Al2O3 and r -GOPS was investigated by using apparent specific area testing, infrared spectrum, temperature programmed desorption-NH3, butamine titration and pyridine absorption techniques. The results show that r -Al2O3 can combine with r -GOPS through the hydroxyl of r-Al2O3 surface and r-GOPS was dispersed over the surface of r-Al2O3. The linkage reaction can proceed according to chemometric. The mass of r -GOPS was rigorous controlled by calculation and weighting. After the Y -Al2O3 was modified and burned at high temperature, it formed very strong Lewis acid centers on its surface and the total amount of acid was increased.The interaction between the linkaged Y -Al2O3 and Pt was characterized by temperature programmed reduction, temperature programmed desorption H2 and H2-O2 titration technique. The results implicated that the interaction of H2PtCl6 and Y -Al2O3 occurs at the site of Al associated with Si. Pt/ r -Al2O3 and Pt-Re/ Y -Al2O3 catalysts prepared by linkage-saturated method had more apparent surface disperses and low-temperature centers and lower reduction temperature. Pt and Pt-Re catalysts prepared by linkage-saturated method can disperse equally on the outer layers of carriers.The activities of catalysts were assayed by micro-catalysis chromatogram technology with the dehydrogen cyclo-oxidation of n-hexane and hydrogen reduction of benzene as the probe. As a result, the activities of the mono-metal catalyst prepared by bond linkage-saturated method with y -Al2O3 as carrier take advantage over that of the catalyst prepared by common saturated method. The activities of the Pt, Re-containing bi-metal supported -type catalysts are better than that of mono-metal catalysts and all the catalysts have high activity of hydrogen and dehydrogenIn the second part, the activities of derived composite oxide obtained from the precursor of CoCr, ZnCr hydrotalicite at different temperatures were assayed. We concluded from the activity assays of catalysts on dehydrogen and dehydration of ethanol that the surface of the catalysts contains more basic center and less acidic center.