Synthesis and Characterization of the Novel BiVO4/CeO2 Nanocomposites

Abstract

Abstract. Novel BiVO4/CeO2 nanocomposites were synthesized by the hydrothermal method combined with the homogeneous precipitation method. The mole ratios of BiVO4:CeO2 were 0.4:0.6, 0.5:0.5, and 0.6:0.4. The obtained BiVO4/CeO2 nanocomposites were characterized by X-ray diffraction (XRD) for phase composition and crystallinity. Particle sizes, morphology and elemental composition of BiVO4/CeO2 nanocomposites were examined by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive X-ray spectroscopy (EDS). The Brunauer, Emmett and Teller (BET) adsorption-desorption of nitrogen gas for specific surface area determination at the temperature of liquid nitrogen was performed on all samples. UV-vis diffuse reflectance spectra (UV-vis DRS) were used to identify the absorption range and band gap energy of the composite catalysts. The results indicated that BiVO4/CeO2 samples retained monoclinic scheelite and fluorite structures. The morphologies of nanocomposite samples consisted of rod-like, plate-like and spheroidal shapes. Specific surface area (SSABET) of the novel synthesized catalysts drastically increased from 38-62 m 2 /g whereas an average BET-equivalent particle diameter (dBET) significantly decreased from 30-12 nm, upon increasing the amount of CeO2 in the BiVO4/CeO2 composite. The absorption spectra of all nanocomposite samples were shifted to the visible region, suggesting the potential application of this novel composite as an active visible-light driven photocatalyst.

Influence of electronic structures of doped TiO2on their photocatalysis

“…Bismuth is another important dopant to improve the photocatalytic performance of TiO 2 . Bismuth oxide compounds such as CaBi 2 O 4 , Bi 2 WO 6 , BiVO 4 , Bi 2 O 3 , BiTaO 4 , Bi 3 O 4 Cl , Bi 2 MoO 6 are also visible light active photocatalysts for decomposition of organic pollutants, hydrogen generation and dye‐sensitized solar cell applications. The d10 configuration of Bi induces hybridization of Bi 6s orbital with O 2p orbital forming a desirable hybridized VB, which increases the mobility of photogenerated holes in the VB and benefits the enrichment of the photocatalytic activity of the bismuth‐based semiconductor oxides .…”

BiOCl/BiVO4 p–n Heterojunction with Enhanced Photocatalytic Activity under Visible-Light Irradiation

“…BiVO 4 exists in three main crystalline phases, monoclinic scheelite, with a band-gap energy of 2.4 eV, and the tetragonal zircon and tetragonal scheelite structures, both of which have a band-gap energy of 3.1 eV. − Of these, monoclinic BiVO 4 has been of great interest for photochemical processes because of its narrow band gap and excellent photocatalytic performance under visible-light illumination. − However, the low separation efficiency of photogenerated electrons and holes and poor electrical conductivity and adsorptive performance, , limit wide application of BiVO 4 in the fields of environmental protection and solar conversion. As a result, many attempts have been made to overcome these disadvantages, including controlling the morphologies, , forming composite structures or heterojunctions, doping or composition tuning, and coupling with oxygen-evolution catalysts. , …”

Discriminatory {040}-Reduction Facet/Ag0Schottky Barrier Coupled {040/110}-BiVO4@Ag@CoAl-LDH Z-Scheme Isotype Heterostructure

“…Relative declination in crystalline domain size suggests elevated charge transfer efficiency over particle/FTO substrate contacts and decreases the water oxidation process attributable to deterioration in crystallinity . However, here the derived crystallite size from Scherrer’s equation is accredited to the grafting of relative low crystalline Ag 0 and the existence of semicrystalline CoAl-LDH (6.02 nm) over crystalline BiVO 4 surfaces rather than a decrease in size of crystalline domains, thus suggesting to have no association toward diverse redox activity. − In addition, a gradual shifting in characteristic signature plane reflections of BiVO 4 {-121} toward higher and lower diffraction angles in BiV@Ag5 and BiV@Ag5@CoA5, respectively, along with a sharp decrease in diffraction intensities, attests the existence of synergistic interaction in the fabricated isotype heterostructures (Figure b).…”