Operando TEM Study of Partial Oxidation of Methane Over Pd Nanoparticles

Area of Science:

• Catalysis
• Materials Science
• Chemical Engineering

Background:

• Methane (CH4) is a key feedstock for syngas production, derived from abundant natural gas.
• Efficient methane conversion is vital to reduce reliance on finite crude oil resources.
• Understanding catalyst mechanisms is essential for optimizing methane conversion reactions.

Purpose of the Study:

• To investigate the nanoscale mechanisms of methane partial oxidation over palladium (Pd) nanoparticles (NPs).
• To identify the active catalyst structures under reaction conditions.
• To provide insights for designing high-performance catalysts for methane conversion.

Main Methods:

• Operando gas-cell transmission electron microscopy (TEM) to observe catalyst transformations in situ.
• Density functional theory (DFT) calculations to elucidate reaction pathways at the atomic level.

Main Results:

• Catalytic reaction onset correlates with Pd NPs transforming into fragmented Pd-PdO NPs.
• The Pd-PdO interface is identified as the active site.
• Metallic Pd facilitates methane dehydrogenation, while PdO aids carbon oxidation.

Conclusions:

• The Pd-PdO interface is critical for efficient methane partial oxidation.
• Insights into active catalyst structures enable rational catalyst design.
• This work advances the understanding of catalytic methane conversion mechanisms.