Unveiling Atomic-Scale Product Selectivity at the Cocatalyst-TiO₂ Interface Using X-Ray Techniques: Insights into...

Area of Science:

• Materials Science
• Surface Chemistry
• Catalysis

Background:

• The interface between cocatalysts and semiconductors is crucial for photocatalysis, affecting carrier and reactant concentration.
• Directly observing this interface's atomic structure is difficult due to material coverings.
• Understanding interface atomic arrangements is key to designing efficient photocatalysts.

Purpose of the Study:

• To investigate the atomic-level microstructural evolution at metal-semiconductor interfaces.
• To correlate interface atomic structure with catalytic product selectivity.
• To develop new methods for studying these critical interfaces.

Main Methods:

• Fabrication of multiple metal-semiconductor interfaces (Ag, Au, Pt) on three TiO2 crystal facets (001, 010, 101).
• Utilized spectroscopies and Density Functional Theory (DFT) calculations to analyze microstructural changes.
• Examined the transformation of titanium-oxygen bonds upon metal loading.

Main Results:

• Observed the conversion of saturated Ti6c-O bonds to unsaturated Ti5c-O and Ti6c-O-Pt bonds on the TiO2-010 facet after Pt loading.
• Demonstrated that these bond transformations directly impact product selectivity.
• Identified CO generation at Ti6c-O-Pt sites and CH4 generation at Pt sites.

Conclusions:

• The atomic arrangement at metal/TiO2 interfaces critically influences photocatalytic performance.
• Interface bond evolution dictates the selectivity of generated products.
• Findings offer insights for developing advanced photocatalytic materials using standard laboratory equipment.