Interfacial Unit-Dependent Catalytic Activity for CO Oxidation over Cerium Oxysulfate Cluster Assemblies

Area of Science:

• Heterogeneous Catalysis
• Materials Science
• Surface Chemistry

Background:

• Atomically precise cerium oxo clusters provide a model system to study structure-property relationships, overcoming the complexity of bulk cerium dioxide.
• Understanding cerium dioxide's catalytic behavior is crucial for applications like CO oxidation.

Purpose of the Study:

• To investigate the catalytic activity of the MCe70 torus family for CO oxidation.
• To explore the influence of the interfacial cation unit on the catalytic performance of cerium oxo clusters.

Main Methods:

• Synthesis and characterization of MCe70 (M = Cd, Ce, Co, Cu, Fe, Ni, Zn) oxo clusters.
• Evaluation of catalytic activity for CO oxidation.
• Temperature-programmed reduction (TPR) and in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) for mechanistic studies.
• Isothermal CO adsorption measurements and density functional theory (DFT) calculations for defect energetics.

Main Results:

• CuCe70 demonstrated superior catalytic activity for CO oxidation compared to other MCe70 catalysts.
• CuCe70 exhibited lower reduction temperatures and faster Ce3+ formation than CeCe70.
• CuCe70 showed increased CO uptake and facilitated oxygen defect formation compared to CeCe70.

Conclusions:

• Atomic-level modification of the interfacial unit in MCe70 clusters significantly impacts reducibility, CO binding, and oxygen vacancy formation.
• CuCe70 serves as a highly active catalyst for CO oxidation, highlighting the importance of interfacial engineering in cerium-based catalysts.