title: Direct Observation of Charge Separation on Anatase TiO2 Crystals with Selectively Etched {001} Facets.
abstract: Synchronous illumination X-ray photoelectron spectroscopy (SIXPS) was employed for the first time to directly identify the photogenerated charge separation and transfer on anatase TiO2 single-crystals with selectively etched {001} facets. More specifically, for the TiO2 crystals with intact {001} and {101} facets, most of photogenerated charge carriers rapidly recombined, and no evident electron-hole separation was detected. With selectively etching on {001} facets, high efficient charge separation via hole transfer to titanium and electron to oxygen was clearly observed. However, when the {001} facets were completely etched into a hollow structure, the recombination for photogenerated electron-hole pairs would dominate again. These demonstrations clearly reveal that the appropriate corrosion on {001} facets could facilitate more efficient electron-hole separation and transfer. As expected, the optimized TiO2 microcrystals with etched {001} facets could achieve a hydrogen generation rate of 74.3 μmol/h/g, which is nearly 7 times higher than the intact-TiO2 crystals.
authors.affiliation: State Key Laboratory for Oxo Synthesis & Selective Oxidation, National Engineering Research Center for Fine Petrochemical Intermediates, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences , Lanzhou 730000, China.
authors.forename: Xiaogang
authors.initials: X
authors.lastname: Liu
authors.affiliation: State Key Laboratory for Oxo Synthesis & Selective Oxidation, National Engineering Research Center for Fine Petrochemical Intermediates, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences , Lanzhou 730000, China.
authors.forename: Guojun
authors.initials: G
authors.lastname: Dong
authors.affiliation: State Key Laboratory for Oxo Synthesis & Selective Oxidation, National Engineering Research Center for Fine Petrochemical Intermediates, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences , Lanzhou 730000, China.
authors.forename: Shaopeng
authors.initials: S
authors.lastname: Li
authors.affiliation: State Key Laboratory for Oxo Synthesis & Selective Oxidation, National Engineering Research Center for Fine Petrochemical Intermediates, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences , Lanzhou 730000, China.
authors.forename: Gongxuan
authors.initials: G
authors.lastname: Lu
authors.affiliation: State Key Laboratory for Oxo Synthesis & Selective Oxidation, National Engineering Research Center for Fine Petrochemical Intermediates, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences , Lanzhou 730000, China.
authors.forename: Yingpu
authors.initials: Y
authors.lastname: Bi