Oxygen Vacancy Formation at Metal‒TiO₂ Interface Yielding Enhanced Photocatalytic Hydrogen Generation

Area of Science:

• Materials Science
• Catalysis
• Nanotechnology

Background:

• Strong Metal-Support Interaction (SMSI) is crucial in heterogeneous catalysis.
• Its role in photon-to-hydrogen conversion, beyond Schottky barriers, is underexplored.
• Coupling metallic nanoparticles with photocatalysts requires deeper investigation.

Purpose of the Study:

• To investigate the effect of Au encapsulation with TiO2 on photocatalytic hydrogen generation.
• To elucidate the mechanism of enhanced charge carrier separation via SMSI-like nanostructures.
• To explore the influence of metal type on oxygen vacancy formation and photocatalytic activity.

Main Methods:

• Fabrication of Au encapsulated with TiO2 overlayer.
• Characterization using Electron Paramagnetic Resonance (EPR) and X-ray Photoelectron Spectroscopy (XPS).
• Computational analysis using Density Functional Theory (DFT).

Main Results:

• SMSI-like nanostructure formation induces oxygen vacancies at the Au-TiO2 interface.
• Oxygen vacancies facilitate charge carrier separation through interfacial band reconstruction.
• DFT calculations confirm Au promotes oxygen vacancy formation, enhancing H2O and MeOH adsorption for H2 evolution.
• Metal type (Pt, Pd, Ag) influences oxygen vacancy formation energy.

Conclusions:

• SMSI-like structures are effective for enhancing photocatalytic hydrogen generation.
• Oxygen vacancies at the metal-semiconductor interface are key to improved performance.
• Photocatalytic activity correlates with the ease of oxygen vacancy formation, tunable by metal choice.