Photocatalytic Activities of Heterojunction Semiconductors Bi₂O₃/BaTiO₃:  A Strategy for the Design of Efficient Combined Photocatalysts

Abstract

The heterojunction semiconductors Bi 2 O 3 /BaTiO 3 were prepared by a milling-annealing method. The powders were characterized by X-ray diffraction (XRD), the Brunauer-Emmett-Teller (BET) method, transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), and UV-vis diffuse reflection spectroscopy (DRS). Their UV-induced photocatalytic activities were evaluated by the degradations of methyl orange and methylene blue. The results generally show that the heterojunction semiconductors Bi 2 O 3 /BaTiO 3 exhibit better photocatalytic properties than the single-phase BaTiO 3 or Bi 2 O 3 . The obviously increased performance of Bi 2 O 3 /BaTiO 3 is ascribed mainly to the electric-field-driven electron-hole separations both at the interface and in the semiconductors. A strategy for the design of efficient heterojunction photocatalysts was proposed. That is, an electron-accepting semiconductor and a hole-accepting semiconductor with matching band potentials, which respectively possess high electron and hole conduction abilities, are tightly chemically bonded to construct the efficient heterojunction structure.

Adsorption and degradation performance of Rhodamine B over BiOBr under monochromatic 532nm pulsed laser exposure

“…To date, several methods have been adopted for the solid-based band/electronic structure measurement and speculation, such as ultraviolet photoelectron spectroscopy (UPS) [28], flatband-potential-determination based photoeletrochemical techniques [29][30][31], atom's Mulliken electronegativity theory [6,27,[32][33][34][35][36][37][38] and density functional theory (DFT) calculation based on plane wave pseudo potential method [39][40][41]. The band-gap width, CB/VB of the catalysts series BiOX (X = F, Cl, Br, I) semiconductor were calculated by means of DFT method [42].…”

Photocatalytic Degradation of Phenol with Fe-Titania Catalysts

“…Thermodynamically, this redox potential has to be more positive than the conduction band potential of the semiconductor. Due to their physicochemical properties, several oxides such as TiO 2 , ZnO, WO 3 , Fe 2 O 3 , SnO, Bi 2 O 3 , and CdS have been used in the photocatalytic experiments [12]. Titania (TiO 2 ) is so far the most useful material for photocatalytic purposes, due to its exceptional optical and electronic properties, chemical stability, non-toxicity, high photocatalytic activity and low cost [3,13].…”

A versatile salicylic acid precursor method for preparing titanate microspheres

“…For a crystalline semiconductor, the optical absorption near the band edge follows the equation, ahν = A (hν−E g ) n/2 , where a, ν, E g and A are the absorption coefficient, light frequency, band gap, and a constant, respectively. Among these factors, the value of n determines the transition characteristics in a semiconductor [29], and for MgTiO 3 /MgTi 2 O 5 , n = 4. The band gaps of the three microspheres are calculated to be ~3.55 eV from the onset of the absorption edge, as shown in Fig.…”