Identification of Highly Selective Surface Pathways for Methane Dry Reforming Using Mechanochemical Synthesis of...

Area of Science:

• Heterogeneous Catalysis
• Materials Science
• Chemical Reaction Engineering

Background:

• Methane dry reforming (DRM) is crucial for converting methane into synthesis gas.
• Developing highly active and selective DRM catalysts remains a significant challenge.
• Palladium supported on ceria (Pd/CeO2) is a promising catalyst system for DRM.

Purpose of the Study:

• To investigate the reaction mechanism of methane dry reforming (DRM) using mechanochemically prepared Pd/CeO2 catalysts (PdAcCeO2M).
• To elucidate the unique Pd-Ce interfaces formed during mechanochemical synthesis.
• To compare the catalytic performance and mechanism of PdAcCeO2M with traditionally synthesized Pd/CeO2 (PdCeO2IW).

Main Methods:

• Mechanochemical synthesis of Pd/CeO2 catalysts.
• In situ characterization techniques (e.g., diffuse reflectance infrared Fourier transform spectroscopy).
• Density functional theory (DFT) calculations.

Main Results:

• PdAcCeO2M catalysts exhibit higher reactivity and selectivity for DRM compared to PdCeO2IW.
• Unique carbon-modified Pd0 and Ce4+/3+ surface arrangement identified in PdAcCeO2M.
• Distinct surface reaction pathways involving linear Pd-CO species and adsorbed HCOO intermediates were observed on PdAcCeO2M.

Conclusions:

• Mechanochemical preparation leads to unique Pd-Ce interfaces that significantly enhance DRM activity.
• The enhanced performance is attributed to a specific carbon-modified surface structure and distinct reaction intermediates.
• PdAcCeO2M offers a promising alternative to conventional catalysts for efficient methane dry reforming.