Tailoring acid–metal functions in molybdenum oxides: Catalytic and XPS-UPS, ISS characterization study

• Preparation of the bifunctional MoO2−x(OH)y deposited on TiO2.
• Neutralization of the Brønsted acid Mo-OH function(s) by the addition of Na or K to the Mo catalyst.
• XPS-UPS and ISS characterization of the catalysts.
• Catalytic reactions of 2-propanol and cyclohexane.

Formation of acid, metal and metal–acid (bifunctional) functions in titania-supported molybdena following controlled partial reduction of MoO3 using hydrogen at different temperatures are monitored by a combination of surface XPS-UPS, ISS techniques. Addition of controlled amount of sodium or potassium alkali metals to the bifunctional MoO2−x(OH)y/TiO2 (MoTi) enabled to neutralize the Brønsted acid Mo-OH functions. Sodium or potassium molybdenum bronze metallic function is formed following the addition of the alkali metal to the Mo salt following its calcination at 773 K. The catalytic functions of these MoTi and Na, KMoTi systems were evaluated for the dehydration/hydrogenation, oxidation reactions of isopropanol to acetone as well as the ring shortening of cyclohexane to methylcyclopentane MCP and its oxidative dehydrogenation to benzene.

Product distribution of cyclohexane on MO3/TiO2, reduced at 873 K, hydrogen flow 40 ml/min.Figure optionsDownload high-quality image (79 K)Download as PowerPoint slide