From Hollow Olive-Shaped BiVO₄ to n−p Core−Shell BiVO₄@Bi₂O₃ Microspheres: Controlled Synthesis and Enhanced Visible-Light-Responsive Photocatalytic Properties

Abstract

In this study, hollow olive-shaped BiVO(4) and n-p core-shell BiVO(4)@Bi(2)O(3) microspheres were synthesized by a novel sodium bis(2-ethylhexyl)sulfosuccinate (AOT)-assisted mixed solvothermal route and a thermal solution of NaOH etching process under hydrothermal conditions for the first time, respectively. The as-obtained products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy, Brunauer-Emmett-Teller surface area, and UV-vis diffuse-reflectance spectroscopy in detail. The influence of AOT and solvent ratios on the final products was studied. On the basis of SEM observations and XRD analyses of the samples synthesized at different reaction stages, the formation mechanism of hollow olive-shaped BiVO(4) microspheres was proposed. The photocatalytic activities of hollow olive-shaped BiVO(4) and core-shell BiVO(4)@Bi(2)O(3) microspheres were evaluated on the degradation of rhodamine B under visible-light irradiation (λ > 400 nm). The results indicated that core-shell BiVO(4)@Bi(2)O(3) exhibited much higher photocatalytic activities than pure olive-shaped BiVO(4). The mechanism of enhanced photocatalytic activity of core-shell BiVO(4)@Bi(2)O(3) microspheres was discussed on the basis of the calculated energy band positions as well. The present study provides a new strategy to enhancing the photocatalytic activity of visible-light-responsive Bi-based photocatalysts by p-n heterojunction.

Porous olive-like BiVO4: Alcoho-hydrothermal preparation and excellent visible-light-driven photocatalytic performance for the degradation of phenol

“…Each microentity contained a lot of mesoand macropores (diameter = 10-60 nm) distributed randomly on the surfaces. Although similarly morphological monoclinic BiVO 4 microentities with or without hollow internal structures were also obtained via a sonochemical or solvo-hydrothermal route by other researchers [39][40][41], the olive-like BiVO 4 materials with porous architectures have not been reported before. With DA as surfactant and at pH = 3.0, the obtained BiVO-DA-3 sample also retained an olive-like morphology and a porous structure (Figs.…”

Fabrication of BiVO4 nanoplates with active facets on graphene sheets for visible-light photocatalyst

“…Even after three cycles, a small decline (<10%) was observed (37.4%), which showed a considerable cycling ability. As an efficient electron scavenger, H 2 O 2 may trap the photo-generated electrons to form highly active·OH species (leading to the total oxidation of phenol) and effectively prevent the recombination of electron-hole pairs, [32] which would enhance the photocatalytic activity of BiVO 4 .…”

“…The absorption band at 1572 cm -1 is characteristic of graphene skeletal vibration (C=C). Some new absorptions appeared in RGO and BVO samples: 1480 cm -1 (-NH stretching vibration of -NH-C=O), 1120 NH stretching vibration of -NH-R), and 930 cm -1 (-NH 2 f the new absorptions provided solid evidence for the reaction of NH in the ethanolamine with the oxygen-containing groups in GO which is further supported by the peak at 3040 cm -1 which is due to the stretch vibration ofmay also result in the formation of aerogel-like structure.Additionally, two new absorptions at 632 and 539 cm -1 are associated w[31] and apical V-O-V bonds,[32] respectively. further confirmed by the results of X-ray photoelectron spectroscopy (XPS) interaction between the BiVO identified by XPS.…”

Effects of citric acid and urea on the structural and morphological characteristics of BiVO4 synthesized by the sol–gel combustion method

“…This is the monoclinic nature of BiVO 4 and Fig. 1 XRD patterns of the samples prepared by the SSR method and the SGC method with different citric acid contents distinguishes from the tetragonal scheelite structure (tBiVO 4 ) [33]. Meanwhile, no diffraction peaks of any other phases or impurities are detected from this pattern, indicating the high purity of the obtained samples.…”