AVS 62nd International Symposium & Exhibition
    Scanning Probe Microscopy Focus Topic Thursday Sessions
       Session SP+BI+NS+SS+TF-ThA

Paper SP+BI+NS+SS+TF-ThA9
Surface Strain-Modulated Binding of Adsorbates on TiO2(110)

Thursday, October 22, 2015, 5:00 pm, Room 212A

Session: Probing Material Growth on the Surface
Presenter: Richard Osgood, Jr., Columbia University
Authors: D.V. Potapenko, Columbia University
R.M. Osgood, Jr., Columbia University
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Mechanical elastic strain is commonly present in nanostructured materials and it has been found to change chemical and electronic properties in a broad range of solids. Systematic study of reactivity-strain relationship on surfaces is difficult because of the fact that only very low values of strain (~0.1%) are achievable through mechanical deformation of macroscopic samples. We have developed a method of preparation of nano-scale strain fields on TiO2 rutile(110) surface by low energy (1keV) Ar ion bombardments combined with specific thermal treatment. Titanium oxide is a brittle material regarded as a prototypical photocatalyst with numerous applications in the areas of solar energy utilization. Subsurface Ar clusters, which are formed through our preparation procedure, cause 5 – 25 nm wide surface deformations with the tensile strain values as high as 4 %. Surface distributions of various molecular and atomic adsorbates on TiO2(110) have been studied with atomically resolved STM imaging. Our results indicate significant strain-related variations in the surface binding properties. In this presentation we will concentrate on surface hydroxyl groups (OH) as a mobile adsorbate. We derive the O-H binding energy from the statistical analysis of the adsorbate distribution. Then we demonstrate a roughly linear relationship between the values of surface strain and the O-H binding energy.