Mesoporous MnCeOx solid solutions for low temperature and selective oxidation of hydrocarbons

Area of Science:

• Catalysis
• Materials Science
• Oxidation Chemistry

Background:

• Developing noble-metal-free heterogeneous catalysts for low-temperature aerobic oxidation of C-H bonds remains a significant challenge.
• Selective oxidation of hydrocarbons under mild conditions is crucial for various chemical processes.

Purpose of the Study:

• To synthesize and evaluate a novel mesoporous Mn0.5Ce0.5Ox solid solution as a highly active catalyst for hydrocarbon oxidation.
• To investigate the catalytic performance and underlying mechanisms of the developed catalyst under mild conditions.

Main Methods:

• Synthesis of a mesoporous Mn0.5Ce0.5Ox solid solution with high manganese doping in a CeO2 lattice.
• Evaluation of the catalyst's performance in the aerobic oxidation of cyclohexane to cyclohexanone/cyclohexanol at 100-120°C.
• Characterization of the catalyst to understand the relationship between its structure and activity.

Main Results:

• The Mn0.5Ce0.5Ox solid solution exhibited high activity and selectivity for hydrocarbon oxidation at 100-120°C.
• Achieved a 17.7% conversion in cyclohexane oxidation at 100°C, outperforming commercial catalysts operating at higher temperatures (140-160°C) with 3-5% conversion.
• The catalyst's performance is attributed to ultrahigh manganese doping, maximizing active surface oxygens and facilitating oxygen vacancy migration.

Conclusions:

• The developed mesoporous Mn0.5Ce0.5Ox solid solution is a highly effective noble-metal-free catalyst for aerobic oxidation of C-H bonds.
• The catalyst's structure, featuring high Mn doping in CeO2, enhances C-H bond activation and oxygen mobility, enabling efficient low-temperature oxidation.
• This research offers a promising alternative to conventional catalysts for selective hydrocarbon oxidation under mild conditions.