Interface-confined oxide nanostructures for catalytic oxidation reactions.

Area of Science:

• Heterogeneous catalysis
• Materials science
• Surface chemistry

Background:

• Heterogeneous catalysts often use metal nanoparticles on oxide supports, but oxides actively influence catalysis.
• Inverse catalysts, where oxides cover metal surfaces, highlight the critical role of oxides.
• Confining active coordinatively unsaturated (CUS) transition metal (TM) cations in heterogeneous systems remains a challenge.

Purpose of the Study:

• To describe a strategy for confining active CUS centers on solid surfaces at the interface of transition metal oxides (TMOs) and noble metals (NMs).
• To investigate the interface-confinement effect in oxide-on-metal inverse catalysts.
• To demonstrate the catalytic performance of these novel systems in oxidation reactions.

Main Methods:

• Fabrication of oxygen-terminated-bilayer TMO nanostructures on NM surfaces.
• Utilizing surface science studies and density functional theory (DFT) calculations on model systems.
• Testing inverse catalysts, particularly TMO-on-Pt (TM = Fe, Co, Ni), in oxidation reactions like CO oxidation.

Main Results:

• Strong binding between TM cations and NM atoms creates stable, oxygen-terminated TMO nanostructures.
• CUS sites at the TMO nanostructure edges exhibit high activity for catalytic oxidation.
• Interface confinement prevents CUS cation deactivation and allows tuning of reactant binding for optimized performance.

Conclusions:

• The interface confinement effect is crucial for stabilizing active CUS centers in inverse oxide-on-metal catalysts.
• These catalysts demonstrate excellent performance in oxidation reactions, such as CO oxidation.
• Inverse oxide-on-metal catalysts offer a promising platform for designing highly efficient novel heterogeneous catalysts.