Defect-engineered nonstoichiometric perovskite hosting high-activity PdO sites for enhanced hydrocarbon oxidation

Area of Science:

• Catalysis
• Materials Science
• Surface Chemistry

Background:

• Supported noble metal catalysts are vital for industrial, environmental, and energy applications.
• Precise control over active site geometry is a significant challenge in catalyst design.
• Conventional methods often rely on particle size control, limiting precise active site engineering.

Purpose of the Study:

• To develop a strategy for atomic-level regulation of noble metal active sites.
• To engineer specific surface morphologies on perovskites as templates for catalyst active sites.
• To investigate the structure-activity relationship in noble metal catalysts for methane oxidation.

Main Methods:

• Perovskite-based surface defect engineering by tailoring La stoichiometry in LaAlO3.
• Creation of distinct surface morphologies (planar, stepped, crater-like) on the perovskite.
• Anchoring and replication of palladium oxide (PdO) nanoparticles on engineered surfaces.
• Evaluation of methane oxidation activity and correlation with Pd step-site density.

Main Results:

• Three distinct surface morphologies were engineered on LaAlO3, serving as templates for PdO nanoparticles.
• The step-rich PdO configuration on La0.9AlO3-δ demonstrated superior methane oxidation activity.
• A linear correlation was observed between Pd step-site density and catalytic performance.
• Low-coordination Pd atoms at step sites were identified as key to enhanced C-H bond activation.

Conclusions:

• Perovskite surface defect engineering enables precise control over noble metal active site geometry.
• Tailored step-rich PdO configurations significantly enhance methane oxidation catalysis.
• This approach provides a generalizable framework for designing efficient and durable oxidation catalysts.