Vapor‐Phase Hydrothermal Transformation of HTiOF3 Intermediates into {001} Faceted Anatase Single‐Crystalline Nanosheets

Abstract For the first time, a facile, one‐pot hydrofluoric acid vapor‐phase hydrothermal (HF‐VPH) method is demonstrated to directly grow single‐crystalline anatase TiO 2 nanosheets with 98.2% of exposed {001} faceted surfaces on the Ti substrate via a distinctive two‐stage formation mechanism. The first stage produces a new intermediate crystal (orthorhombic HTiOF 3 ) that is transformed into anatase TiO 2 nanosheets during the second stage. The findings reveal that the HF‐VPH reaction environment is unique and differs remarkably from that of liquid‐phase hydrothermal processes. The uniqueness of the HF‐VPH conditions can be readily used to effectively control the nanostructure growth.