One-pot template-free synthesis of heterophase BiVO₄microspheres with enhanced photocatalytic activity

Abstract

5One-pot template-free hydrothermal method was developed for the fabrication of BiVO 4 microsphere with tetragonal-monoclinic heterophase structure. XRD and HRTEM characterizations confirmed the formation of heterophase structure. It was found that the molar ratio of Bi/V and hydrothermal time were critical parameters in the yield of the spherical morphology and heterophase structure. Benefiting from the unique morphology and existence of heterophase, the as-prepared BiVO 4 microsphere exhibited 10 improved efficiency for RhB degradation in comparison with pure monoclinic scheelite-type BiVO 4 and tetragonal zircon-type BiVO 4 . EPR and PL-TA techniques proved that the photoinduced active species were involved in the photocatalytic degradation of RhB. The enhanced photocatalytic performance can be attributed to the more effective separation of photogenerated carriers generated in the heterophase BiVO 4 system, as evidenced by the electrochemical measurement. 15 65

Co2+ substituted for Bi3+ in BiVO4 and its enhanced photocatalytic activity under visible LED light irradiation

“…Monoclinic scheelite bismuth vanadate (m-s BiVO 4 ), a p-type semiconductor with a direct band gap (E g ) of 2.4 eV, has generated considerable interest as a visible light-responsive photocatalyst. [1][2][3][4] Reportedly, different morphologies of monoclinically structured BiVO 4 crystallites, such as nanospheres, 5 nanorods, 6,7 nanoowers, 8 nanosheets, 9 nanotubes, [10][11][12] olive, 13,14 and hyperbranched, 15 have been clearly created by the hydrothermal or solvothermal technique. Nevertheless, the poor charge transport and weak surface adsorption properties associated with pristine BiVO 4 could cause prompt recombination of photogenerated electron-hole pairs, reducing its overall photocatalytic efficiency.…”

Synthesis, surface and optical properties of Ag2CaV4O12 nanoparticles for dye removal under visible irradiation

“…Usually these active species have different contributions in the photocatalysis process. For example, Hu et al [29] recently have reported the performance of the wellknown BiVO 4 photocatalyst. The improved photocatalytic activity was ascribed to the most effectively separation efficiency of photogenerated carriers generated in the BiVO 4 system.…”

“…O $À 2 and · OH had been detected in the suspension of BiVO 4 microsphere. Based on free-radical scavenging experiments, the decomposition of RhB was driven mainly by the participation of O $À 2 and a lesser extent by the participation of holes and · OH [29]. The experiment was conducted to investigate the photocatalytic species in this work.…”

Photocatalytic Removal of Organics over BiVO4-Based Photocatalysts

“…This BiVO 4 sample showed a high phenol conversion (100%) within 90 min of natural sunlight illumination, which was related to the morphology of BiVO 4 (surface area = 10 m 2 /g). [6], (c) [22], (d) [29], (e) [30], (f) [31], (g) [32], (h) [33], (i) [34], and (j) [35]. An one-pot template-free hydrothermal method was developed for the fabrication of BiVO 4 microspheres with a tetragonal-monoclinic heterophasic structure [30].…”

“…[6], (c) [22], (d) [29], (e) [30], (f) [31], (g) [32], (h) [33], (i) [34], and (j) [35]. An one-pot template-free hydrothermal method was developed for the fabrication of BiVO 4 microspheres with a tetragonal-monoclinic heterophasic structure [30]. The average diameter, bandgap energy, and BET surface area of the as-prepared The superior activity of the m-BiVO 4 sample was attributed to two reasons: (i) the BET surface area of the hierarchical hollow spheres was 10.6 m 2 /g, the higher surface area provided not only more surface reached by the visible light but also more active sites, which would result in good photocatalytic performance and (ii) the large hollow space inside the microspheres greatly decreased the density of m-BiVO 4 , thus rendering them to be easily suspended in water.…”