Methanol conversion over a Pd5Cu/Al2O3-CeO2 catalyst: an FT-IR study and reaction mechanism

Area of Science:

• Materials Science
• Catalysis
• Chemical Engineering

Background:

• Methanol conversion is a key process for producing syngas and methane.
• Developing efficient and stable catalysts is crucial for optimizing these reactions.

Purpose of the Study:

• To synthesize and characterize a Pd-Cu mixed oxide catalyst supported on Al2O3-CeO2.
• To investigate the catalytic activity of this material in methanol conversion.
• To elucidate the reaction mechanism, particularly at higher temperatures.

Main Methods:

• Wet impregnation method for catalyst preparation.
• Thermal stability and surface area analysis up to 873 K.
• X-ray diffraction (XRD) for phase identification.
• Infrared (IR) spectroscopy for reaction intermediate analysis.

Main Results:

• The catalyst, Pd(5)CuO(x)/Al(2)O(3)-CeO(2), is a thermally stable mesoporous material with a surface area of 170 m²/g at 873 K.
• Characterization revealed a cubic CeO(2) phase and well-dispersed Cu-Pd clusters.
• Methanol conversion yielded syngas (CO + H2) between 473-723 K and methane at higher temperatures.
• Absence of oxygenated intermediates suggested a non-standard reaction pathway.

Conclusions:

• The Pd(5)CuO(x)/Al(2)O(3)-CeO(2) catalyst demonstrates high activity and stability for methanol conversion.
• The reaction mechanism for methanol to methane conversion likely involves a carbide intermediate.
• The catalyst's properties, including dispersion and support interaction, are critical for its performance.