Advances and recent applications in high-energy {001} facets of anatase TiO2: A review

Abstract

Surface control is a crucial influencing factor for the performance of semiconductors, especially TiO₂ photocatalyst. Normally, anatase TiO₂ is accessible with exposed stable {101} facets. Nevertheless, the surface energy of {001} facets with 0.90 J·m⁻² is 2.05 times higher than that of {101} facets. Therefore, anatase TiO₂ with high-energy {001} facets has attracted much attention and been recognized for some special properties. In this review, we profoundly focus on the special {001} facets of anatase TiO₂ from synthesis, unique physicochemical features to recent applications. Here, we provide the detailed surface-controlled growth approaches of F as a capping agent and the F-free route. The morphologies of TiO₂ with {001} facets are presented as single nanocrystals or hierarchically assembled crystals. Particularly, we summarize the physicochemical features of {001} facets, including efficient oxygen site, strong interaction with reactants, excellent photothermocatalytic synergetic effect and unique surface defects. These unique features have promoted the recent applications of {001} facets, which are widely used in VOCs degradation, CH₄ conversion, CO₂ reduction, H₂ production, water oxidation, antibiotic removal, and NO oxidation, etc. Through this review, the research on anatase TiO₂ with {001} facets, and even the surface control of other semiconductor materials can be further inspired.