Nanostructured, mesoporous Au/TiO(2) model catalysts - structure, stability and catalytic properties

Area of Science:

• Materials Science
• Catalysis
• Nanotechnology

Background:

• Developing model catalytic systems is crucial for understanding complex reaction mechanisms.
• Titanium dioxide (TiO2) supported gold (Au) nanoparticles are promising catalysts for oxidation reactions.
• Realistic transport properties in model catalysts are essential for accurate mechanistic studies.

Purpose of the Study:

• To prepare and characterize planar Au/TiO2 thin-film model catalysts with controlled properties.
• To evaluate the catalytic activity of these model systems using carbon monoxide (CO) oxidation.
• To assess the suitability of these thin-film models for studying catalytic processes and transport limitations.

Main Methods:

• Fabrication of mesoporous TiO2 films via spin-coating, followed by Au nanoparticle deposition-precipitation.
• Characterization using X-ray diffraction (XRD), transmission electron microscopy (TEM), N2 adsorption, ICP-OES, and X-ray photoelectron spectroscopy (XPS).
• Catalytic evaluation via CO oxidation, with reactivity measured by scanning mass spectrometry.

Main Results:

• Successfully prepared Au/TiO2 thin-film model catalysts with ~2 nm Au nanoparticles.
• Structural and chemical properties closely resemble dispersed Au/TiO2 supported catalysts.
• Catalytic activity for CO oxidation linearly increased with film thickness, indicating negligible transport limitations.

Conclusions:

• Planar Au/TiO2 thin-film model catalysts are suitable for studying catalytic reactions due to their realistic properties.
• The absence of significant transport limitations allows for direct investigation of intrinsic catalytic behavior.
• These model systems provide a valuable platform for advancing the understanding of heterogeneous catalysis.