KPFM/AFM imaging on TiO₂(110) surface in O₂ gas

Area of Science:

• Surface science
• Materials science
• Physical chemistry

Background:

• Rutile titanium dioxide (TiO2) is a crucial material in catalysis and surface chemistry.
• Understanding surface adsorbates and their electronic properties is key to controlling catalytic reactions.
• Atomic force microscopy (AFM) and Kelvin probe force microscopy (KPFM) are powerful tools for surface characterization.

Purpose of the Study:

• To perform high-speed atomic resolution imaging of adsorbates on rutile TiO2(110) surfaces.
• To investigate the local contact potential difference (LCPD) changes associated with adsorbed species.
• To explore the potential of KPFM/AFM for observing dynamic catalytic processes at the atomic scale.

Main Methods:

• High-speed atomic force microscopy (AFM) for topographic imaging.
• Kelvin probe force microscopy (KPFM) for measuring local contact potential difference (LCPD).
• Imaging performed on a hydroxylated rutile TiO2(110) surface in an O2 gas environment at 1 frame per minute.

Main Results:

• Achieved atomic resolution KPFM/AFM imaging at a rate of 1 frame min⁻¹.
• Observed distinct adsorbates on the hydroxylated TiO2(110) surface, identified as potential oxygen adatoms (Oa), hydroperoxyls (HO2), or terminal hydroxyls (OHt).
• Detected changes in topography and LCPD of the adsorbates following adsorption, attributed to charge transfer.

Conclusions:

• The study demonstrates the capability of high-speed KPFM/AFM for atomic-resolution surface analysis.
• Observed adsorbate-induced changes suggest charge transfer mechanisms influencing surface properties.
• This advanced imaging technique holds significant potential for in-situ observation of catalytic behavior at the atomic level.