Highly efficient Co single-atom catalyst for epoxidation of plant oils

Area of Science:

• Green Chemistry
• Catalysis
• Materials Science

Background:

• Epoxidation of plant oils is crucial for producing sustainable chemicals like plasticizers and lubricant additives.
• Traditional methods utilize harsh acids or expensive peroxides, posing environmental and economic challenges.
• Developing efficient and eco-friendly epoxidation catalysts is a key research area.

Purpose of the Study:

• To develop a sustainable and efficient method for plant oil epoxidation using molecular oxygen as the oxidant.
• To investigate the catalytic performance of a cobalt nitrogen carbon supported on silica (Co-N-C/SiO2) single-atom catalyst for this transformation.
• To elucidate the reaction mechanism and assess the catalyst's reusability.

Main Methods:

• Synthesis and characterization of Co-N-C/SiO2 single-atom catalyst using advanced techniques (HAADF-STEM, EXAFS).
• Epoxidation of methyl oleate and crude plant oils using O2 under mild conditions (35 °C, 0.1 MPa O2).
• Kinetic studies and Electron Paramagnetic Resonance (EPR) experiments to probe the reaction mechanism.

Main Results:

• The Co-N-C/SiO2 catalyst demonstrated high activity and selectivity (99%) for methyl oleate epoxidation at full conversion.
• Effective epoxidation was achieved even with crude plant oils, yielding good amounts of epoxides.
• The catalyst exhibited excellent reusability over five cycles without significant loss of performance.

Conclusions:

• Co-N-C/SiO2 single-atom catalyst offers a sustainable and efficient route for plant oil epoxidation using O2.
• The catalyst's stability, reusability, and effectiveness with crude oils highlight its practical potential.
• A reaction mechanism involving superoxide radicals was proposed, providing insights into the catalytic process.