PNNL

Abstract

Titanium dioxide is the most investigated single-crystalline system in the surface science of metal oxides, and the literature on rutile (110), (100), (001), and anatase surfaces is reviewed. This paper starts with a summary of the wide variety of technical fields where TiO2 is of importance. The bulk structure and bulk defects (as far as relevant to the surface properties) are briefly reviewed. Rules to predict stable oxide surfaces are exemplified on rutile (110). The surface structure of rutile (110) is discussed in some detail. Theoretically predicted and experimentally determined relaxations of surface geometries are compared, and defects (step edge orientations, point and line defects, impurities, surface manifestations of crystallographic shear planes—CSPs) are discussed, as well as the image contrast in scanning tunneling microscopy (STM). The controversy about the correct model for the (1×2) reconstruction appears to be settled. Different surface preparation methods, such as reoxidation of reduced crystals, can cause a drastic effect on surface geometries and morphology, and recommendations for preparing different TiO2(110) surfaces are given. The structure of the TiO2(100)-(1×1) surface is discussed and the proposed models for the (1×3) reconstruction are critically reviewed. Very recent results on anatase (100) and (101) surfaces are included.