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Plasma Treatment-reduced Pd/Al2O3 Catalyst For Glucose Oxidation To Sodium Gluconate

Posted on:2007-11-07Degree:MasterType:Thesis
Country:ChinaCandidate:F H GuoFull Text:PDF
GTID:2121360212980335Subject:Chemical processes
Abstract/Summary:PDF Full Text Request
Glucose oxidation to gluconic acid is an important reaction for carbohydrate oxidation, which is an important method utilizing the renewable resource. Gluconic acid is conventionally produced via fermentation of glucose. The heterogeneous catalytic oxidation has attracted increasing interests because it is a simple, quick, and environmentally friendly process. Many reported investigations focused on the modification of Pt/C with the addition of promoter like bismuth, thallium and platinum. Aluminum, as the support, is safer to the environment and can be more easily separated from the product, compared with the active carbon. These metal-loaded catalysts are generally reduced with hazardous chemicals. It is necessary to develop a green method to reduce catalyst with low cost. In this work, a glow discharge plasma treatment has been utilized to reduce Pd/Al2O3, which leads to a new and green reduction method for metal-loaded catalyst. The resulted catalyst was applied for the oxidation of glucose.The impregnated Pd/Al2O3 was treated with a glow discharge plasma and characterized by TEM, XPS, XRD and AFM. It is found that the impregnated metal ions are reduced into metallic Pd, indicating that the glow discharge plasma treatment is an effective catalyst reduction method. The obtained metals directly from the plasma treatment are amorphous and calcinations in inert atmosphere make them into well crystals. The metal dispersion is improved compared with the H2-reduced sample. As a reduction method, plasma treatment can effectively reduce oxides into metals at the ambient condition. This has the advantage of chemical reduction, which avoids the sintering of active metal and possible negatively thermal effect. Moreover, the plasma method improves the high dispersion of active metal. Since the plasma treatment does not use any chemicals, it is safe and nontoxic. This simple method has wide potentials in the preparation of the metal-loaded catalysts.In the reaction of glucose oxidation, the catalysts reduced by plasma treatment shows identical activity to those reduced with H2. The plasma-reduced catalyst shows a conversion of 95.8% with a selectivity of 97.4% for sodium gluconate. The difference in deactivation mechanism, activity and stability of the two catalysts in the reaction is also discussed...
Keywords/Search Tags:plasma-reduce, Pd/Al2O3 catalyst, glucose oxidation, green chemical technology
PDF Full Text Request
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