First-principles study on unidirectional proton transfer on anatase TiO₂ (101) surface induced by external electric...

Area of Science:

• Surface Science
• Computational Chemistry
• Materials Science

Background:

• Proton transfer (PT) is crucial in many chemical and biological processes.
• Understanding surface PT on metal oxides like titanium dioxide (TiO2) is essential for catalysis and electronics.
• The influence of external electric fields (EF) on surface PT is not fully understood.

Purpose of the Study:

• To investigate the effect of electric fields (EF) on hydrogen or proton transfer (PT) via hydroxyl groups on an anatase TiO2 (101) surface.
• To determine how EF magnitude and orientation influence the preferred PT pathway.
• To elucidate the mechanism by which EFs modify the PT energy profile.

Main Methods:

• First-principles density functional theory (DFT) calculations.
• Application of the modern theory of polarization.
• Simulation of unidirectional surface PT under external EFs with varying orientations.

Main Results:

• The preferred PT pathway is sensitive to the magnitude and direction of the applied EF.
• The EF's influence on the PT energy profile differs significantly from classical point-charge models.
• EF-induced changes in PT are primarily driven by the rearrangement of chemical bonds at the water-surface interface.

Conclusions:

• External electric fields can effectively control surface proton transfer on TiO2.
• The mechanism involves intricate interfacial bond rearrangements, not just simple electrostatic work.
• This work provides fundamental insights into manipulating surface reactions with electric fields.