Structure Sensitivity of Au-TiO₂ Strong Metal-Support Interactions

Area of Science:

• Heterogeneous Catalysis
• Materials Science
• Surface Chemistry

Background:

• Strong metal-support interactions (SMSI) are crucial in heterogeneous catalysis, influencing catalyst performance.
• Understanding SMSI in gold-titanium dioxide (Au/TiO2) systems is key for developing efficient catalysts.

Purpose of the Study:

• To investigate how gold nanoparticle (NP) size and titanium dioxide (TiO2) facets affect Au-TiO2 SMSI.
• To elucidate the structural and electronic properties of SMSI-affected Au/TiO2 catalysts.
• To correlate SMSI characteristics with catalytic activity in CO oxidation.

Main Methods:

• Synthesis of Au/TiO2 catalysts with varying Au NP sizes and TiO2 facets.
• Characterization of SMSI using techniques to determine overlayer composition and electronic structure.
• Computational modeling to understand charge transfer and interface properties.
• Low-temperature CO oxidation reaction studies to assess catalytic activity.

Main Results:

• Au NP size and TiO2 facets significantly influence Au-TiO2 SMSI.
• Larger Au NPs (ca. 5 nm) and specific TiO2 facets ({001}, {100}) promote SMSI more readily than smaller NPs (ca. 2 nm) and {101} facets.
• SMSI results in TiO2-x overlayers with specific oxidation states and charge transfer, enhancing lattice oxygen activation and CO oxidation activity.

Conclusions:

• The extent of Au-TiO2 SMSI is tunable by controlling Au NP size and TiO2 facet exposure.
• Engineered SMSI leads to improved catalytic performance in low-temperature CO oxidation.
• This work provides fundamental insights into SMSI and a strategy for catalyst design.