Highly Efficient and Stable Methane Dry Reforming Enabled by a Single-Site Cationic Ni Catalyst

Area of Science:

• Catalysis
• Materials Science
• Chemical Engineering

Background:

• Zeolite-supported nickel (Ni) catalysts are crucial for methane dry reforming (DRM).
• Typically, Ni is reduced to its metallic state to function as the active site.
• Understanding Ni's role in zeolite frameworks is key to improving catalyst performance.

Purpose of the Study:

• To investigate the catalytic behavior of Ni incorporated into the MFI zeolite framework for DRM.
• To elucidate the reaction mechanism of cationic Ni sites in comparison to metallic Ni.
• To develop more stable and active Ni-based catalysts for DRM.

Main Methods:

• Ligand-protected synthesis for high Ni incorporation into MFI zeolite.
• Dry reforming of methane (DRM) reaction at 600 °C.
• Theoretical calculations and experimental validation of reaction intermediates.

Main Results:

• Ni incorporated into the MFI zeolite framework retained its cationic state during DRM.
• Cationic Ni sites exhibited higher apparent catalytic activity and stability than metallic Ni.
• Formation of metal-oxygen (Ni^δ+-O^(2-ξ)-) pairs as active sites was identified.

Conclusions:

• Cationic Ni-MFI catalysts promote methane C-H bond dissociation via a unique mechanism.
• The CH oxidation pathway on cationic Ni sites inhibits coke formation.
• These findings guide the design of advanced Ni-based DRM catalysts.