Manipulating Atomic Structures at the Au/TiO₂ Interface for O₂ Activation.

Area of Science:

• Materials Science
• Surface Chemistry
• Catalysis Science

Background:

• The metal/oxide interface is crucial for heterogeneous catalysis, but its atomic-level mechanisms remain unclear.
• Understanding interfacial atomic structures is key to controlling catalytic activity.

Purpose of the Study:

• To investigate how atomic structure manipulation at the gold/titanium dioxide (Au/TiO2) interface affects electron distribution and oxygen activation.
• To elucidate the role of interfacial atomic structures in CO oxidation catalysis.

Main Methods:

• Fabrication and characterization of Au/TiO2 interfaces with varying atomic structures (defect-free vs. oxygen vacancy-rich).
• In-situ spectroscopic analysis to probe interfacial electron transfer and oxygen molecule interactions.
• CO oxidation activity measurements to quantify catalytic performance.

Main Results:

• Defect-free Au/TiO2 interfaces facilitate electron transfer from Ti3+ to Au nanoparticles and then to O2, forming Au-O-O-Ti species and enhancing O2 activation.
• Oxygen vacancy-rich Au/TiO2 interfaces trap electrons at oxygen vacancies (Vo), hindering O2 activation and resulting in significantly lower CO oxidation activity (ca. 34 times lower).
• Calcination treatment can release trapped electrons from interfacial Vo, thereby promoting O2 activation.

Conclusions:

• Atomic structure at the metal/oxide interface dictates interfacial electron distribution and catalytic activity.
• Optimizing interfacial atomic structures, such as creating defect-free interfaces, is a promising strategy for enhancing heterogeneous catalysis.
• This study provides an atomic-level mechanistic understanding for designing efficient catalysts.