Vapor Phase Oxidation of Benzyl Alcohol over Nano Au/SBA-15 Catalysts: Effect of Preparation Methods

• Published in: Catalysis letters Vol. 146; no. 1; pp. 35 - 46
• Main Authors: Kumar, Ashish, Kumar, Vanama Pavan, Srikanth, Amirineni, Vishwanathan, Venkataraman, Chary, Komandur V. R.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.01.2016; Springer; Springer Nature B.V
• Subjects: Alcohol; Aldehydes; Analysis; Benzaldehyde; Benzyl alcohol; Catalysis; Catalysts; Catalytic activity; Chemical properties; Chemical synthesis; Chemisorption; Chemistry; Chemistry and Materials Science; Conversion; Deposition; Gold; Industrial Chemistry/Chemical Engineering; Methods; Organometallic Chemistry; Oxidation; Oxidation-reduction reactions; Particle size distribution; Physical Chemistry; Polyols; Pore size distribution; Porosity; Precipitation (Meteorology); Reaction time; Selectivity; Vapor phases; Oxidation; Benzyl alcohol; SBA-15; Gold nanoparticles; Benzaldehyde
• ISSN: 1011-372X; 1572-879X
• DOI: 10.1007/s10562-015-1656-7

Au/SBA-15 nano catalysts were synthesized from four different methods, viz., homogeneous deposition–precipitation, micro-emulsion, impregnation and polyol, and their catalytic activities were investigated for the vapor phase oxidation of benzyl alcohol to benzaldehyde. The physico-chemical properties of the catalysts were characterised by XRD, TEM, BET surface area, pore size distribution, CO-chemisorption and XPS techniques. The structural data of the catalysts along with their catalytic studies indicate that the presence of very small metallic Au 0 species with particle size of 7–8 nm, was responsible for the higher activity observed in the vapor phase oxidation of benzyl alcohol reaction. The title reaction, though industrially important, was used as a test reaction to investigate firstly, the influence of different preparation methods on the uniform dispersion of gold particles on the support SBA-15 and to understand the metal-support interaction in Au/SBA-15 catalysts, and secondly, to study the catalytic performance of the catalyst (Au/SBA-15) in terms of activity, selectivity and stability over a period of reaction time. The conversion of benzyl alcohol was found to increase with decrease in the size of gold particles. Smaller gold particles with higher percentage of dispersion on the support SBA-15 had a beneficial effect on the catalytic activity. Among the four methods used for the preparation of gold on SBA-15 support, the catalyst prepared by homogeneous deposition–precipitation method showed the best performance in terms of conversion, selectivity for benzaldehyde and longer catalyst life. Graphical Abstract Vapor phase oxidation of benzyl alcohol over nano Au/SBA-15 catalysts.