Spatially Separated Active Sites Enable Selective CO Oxidation Reaction on Oxide Catalyst

Area of Science:

• Catalysis
• Materials Science
• Surface Chemistry

Background:

• Developing efficient non-noble metal catalysts for selective oxidation is crucial for many industrial processes.
• Understanding the origin of selectivity in oxide-catalyzed reactions is often challenging.

Purpose of the Study:

• To identify the atomic-level mechanisms governing selective oxidation reactions on oxide catalysts.
• To elucidate the role of surface structure in achieving selectivity for CO oxidation over H2.

Main Methods:

• Utilized high-pressure surface imaging techniques.
• Performed theoretical calculations to analyze reaction pathways and energy barriers.
• Investigated ultrathin manganese oxide (Mn3O4) surfaces.

Main Results:

• Identified spatially separated active sites for O2 activation and H2 adsorption on Mn3O4.
• Demonstrated that H2 dissociation and diffusion face higher energy barriers compared to CO reaction.
• Revealed that CO can directly react with adsorbed O2 via an Eley-Rideal mechanism.

Conclusions:

• Spatially separated active sites on Mn3O4 surfaces are key to selective CO oxidation over H2.
• The distinct arrangements of Mn-O and Mn-Mn pairs dictate reaction selectivity.
• Provides atomic-level insights into structure-dependent selective oxidation on oxide catalysts.