Electronic band structure and visible-light photocatalytic activity of Bi₂WO₆: elucidating the effect of lutetium doping

Abstract

International audienceBismuth tungstate and 5% Lu-doped bismuth tungstate photocatalysts were synthesized by coprecipitation method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-Vis diffuse reflectance spectra (DRS), and Brunauer-Emmett-Teller (BET) surface area. The effect of lutetium doping on electronic structure was investigated using density functional theory calculations (DFT). The change of morphological and optical band gap was conditioned by lutetium doping. Under visible light irradiation, the as-prepared sheet-like Lu-Bi2WO6 sample exhibits the highest visible-light-responsive photocatalytic performance than pure Bi2WO6 for the degradation of Methylene Blue (MB). The photocatalytic mechanism was explained on the basis of electrochemical impedance spectroscopy (EIS), photoluminescence (PL) spectra, active trapping measurements and optoelectronic properties

Bi2WO6–BiOCl heterostructure with enhanced photocatalytic activity for efficient degradation of oxytetracycline

“…The convergence criterion of self-consistent calculations for ionic relaxations was set to 1 × 10 –5 eV atom −1 . The corresponding lattice parameter of unit cell for Bi 2 WO 6 was calculated as a = 5.55 Å, b = 16.85 Å and c = 5.58 Å and that for BiOCl was a = b = 3.91 Å and c = 7.84 Å, which were in good agreement with previous reports 35 , 36 . For the Bi 2 WO 6 (020)/BiOCl (010) interface model, a 3 × 4 Bi 2 WO 6 (020) surface slab was used to match a 7 × 3 BiOCl (010) surface slab.…”

Photo/Electrocatalytic Properties of Nanocrystalline ZnO and La–Doped ZnO: Combined DFT Fundamental Semiconducting Properties and Experimental Study

“…In order to further study the photocatalytic mechanism, the main active species generated during the process of RhB degradation were investigated by the trapping experiments using scavenger molecules. The trapping tests for OH • , O 2 •− and h + were carried out respectively using isopropanol (IPA), ascorbic acid (AS) and Ethylenediaminetetraacetic acid (EDTA) ,– . Figure shows the effect of these scavengers on the degradation of RhB, we find that in the presence of ascorbic acid and EDTA, the degradation efficiency was reduced to 25% and 36%, respectively.…”

“…However, photostability of the materials in heterostructure divices and contact effectiveness did not meet the need for practical applications . It is well known that doping can exerts substantial influences in modifying the electronic band structure and construction of favourable surface sites in semiconductors, thus, the quantum efficiency for photocatalytic activity will be promoted through the mobility of charge carriers between valence band and conduction band. In addition, developing a shape‐controlled morphologies with high surface area is absolutely needed for the application of ZnO with high photocatalytic applications, as a result, different well‐defined shapes and morphologies were obtained such as spindles and nanoneedles, nanoneedles, nanorings and microflowers …”

Preparation and Characterization of Porous Carbon@ZnO‐NPs for Organic Compounds Removal: Classical Adsorption Versus Ultrasound Assisted Adsorption

“…Different physicochemical methods including adsorption, chemical oxidation, coagulation, flocculation, and photocatalytic reactions have been tested for the treatment of wastewater colored by dyes . It is noteworthy to note that magnetic and dielectric oxides have been also used for environmental remediation .…”