Study on mechanism of photocatalytic performance of La-doped TiO{sub 2}/Ti photoelectrodes by theoretical and experimental methods

Journal Article · Thu Dec 15 00:00:00 EST 2011 · Journal of Solid State Chemistry

OSTI ID:21612822

Xin Yanjun, E-mail: [e-mail] ^[1]; Liu Huiling, E-mail: [e-mail] ^[2]

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1. School of Resource and Environment, Qingdao Agricultura1 University, Qingdao 266109 (China)
2. State Key Laboratory of Urban Water Resources and Environment (SKLUWRE), Department of Environmental Science and Engineering, Harbin Institute of Technology, Huanghe Road 73, Nangang District, Harbin 150090 (China)

TiO{sub 2} photoelectrodes with various nanostructures have been successfully prepared by the anodization method. The morphology, microstructure and optical properties of as-prepared photoelectrodes were studied by scanning electron microscopy (SEM), X-ray diffraction (XRD), ultraviolet/visible light diffuse reflectance spectra (UV/vis/DRS), surface photovoltage spectroscopy (SPS) and photocurrent. The electronic structure and optical properties of La doped/undoped TiO{sub 2} photoelectrodes with different crystal structures were calculated by the density function theory. The photocatalytic and photoelectrocatalytic activities of as-prepared photoelectrodes were evaluated. The results showed that the anodization potentials played a crucial role in the surface morphology and microstructure. Both results of theoretical calculations and experimental tests demonstrated that La-doped photoelectrodes were more sensitive to light than undoped one. The difference of photoelectrodes performance was ascribed to the crystal configuration, impurity energy levels and long-range orientation moving of photogenerated carriers. - Graphical abstract: Photophysical chemistry processes in as-prepared TiO{sub 2} photoelectrodes. Overall scheme of TiO{sub 2} photoelectrodes: (A) movement of photoelectrons and holes without bias potentials; (B) movement of photoelectrons and holes at applied bias potentials; (a) and (b) were the transmission of photogenerated electrons and holes of local enlargement of (A) (black open circle): (a) photoelectrons movement in P-TiO{sub 2} photoelectrodes and La-TiO{sub 2} photoelectrodes, the red dot line denotes the top of valence band (VB) and the bottom of conduction band (CB) of pure photoelectrodes; (b) photoelectrons movement in P-160 and La-160 TiO{sub 2} photoelectrodes (mixed crystal phase). The number refers to as follows: (1) transmission process of photoelectrons and holes; (2) recombination process of photoelectrons and holes. Arrows represent the moving direction of photoelectrons. Highlights: Black-Right-Pointing-Pointer Morphology and structure of La-doped photoelectrodes. Black-Right-Pointing-Pointer Band gap and electric structure of La-doped and undoped photoelectrodes. Black-Right-Pointing-Pointer Optical, PECH, PC and PEC properties of La-TiO{sub 2} photoelectrodes. Black-Right-Pointing-Pointer Transmission process of photoelectron-hole pairs in La-TiO{sub 2} photoelectrodes.

• OSTI ID: 21612822
• Journal Information: Journal of Solid State Chemistry, Vol. 184, Issue 12; Other Information: DOI: 10.1016/j.jssc.2011.10.017; PII: S0022-4596(11)00558-5; Copyright (c) 2011 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ANODIZATION
CRYSTAL STRUCTURE
CRYSTALS
DENSITY
DOPED MATERIALS
ELECTRONIC STRUCTURE
ENERGY LEVELS
MICROSTRUCTURE
MORPHOLOGY
NANOSTRUCTURES
OPTICAL PROPERTIES
PHOTOCATALYSIS
RECOMBINATION
SCANNING ELECTRON MICROSCOPY
SPECTROSCOPY
SURFACES
TITANIUM OXIDES
TRANSMISSION
VISIBLE RADIATION
X-RAY DIFFRACTION
CATALYSIS
CHALCOGENIDES
CHEMICAL COATING
COHERENT SCATTERING
CORROSION PROTECTION
DEPOSITION
DIFFRACTION
ELECTROCHEMICAL COATING
ELECTROLYSIS
ELECTROMAGNETIC RADIATION
ELECTRON MICROSCOPY
LYSIS
MATERIALS
MICROSCOPY
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
RADIATIONS
SCATTERING
SURFACE COATING
TITANIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS