One-Pot Template-Free Hydrothermal Synthesis of Monoclinic Hollow Microspheres and Their Enhanced Visible-Light Photocatalytic Activity

The effect of the amount of BiVO 4 as visible light sensitizer on the photocatalytic activity of BiVO 4 /3DOM TiO 2 nanocomposites was highlighted. The low amount of BiVO 4 nanoparticles favors the transfer of photogenerated electrons to 3DOM TiO 2 while photogenerated electrons will remain at the surface of BiVO 4 at high amount of BiVO 4 , leading to the recombination of electrons-holes and reduced photocatalytic activity. 1 0 0.6 0.4 0.2 0.08 0.04 0.0209 0.0381 0.0256 0.0152 0.110 0.0078 0.0062 100 75 50 25 10 5 0 0.040 0.035 0.030 0.025 0.020 0.015 0.010 0.005 0.000 Rate Constant (min -1 ) mol % BiVO 4 -1 0 1 2 3 E (NHE) CB VB O 2 /O 2 .-OH . /H 2 O Oxidation Highlights -BiVO 4 @3DOM TiO 2 exhibit highly enhanced visible light photocatalytic activity -The effect of the amount of BiVO 4 as visible light sensitizer is highlighted -The electronic interactions BiVO 4 /TiO 2 lead to an improved charge separation -High BiVO 4 content leads to the accumulation of the electron/hole pairs at the surface of the BiVO 4 4 Abstract A series of BiVO 4 /3DOM TiO 2 nanocomposites have been synthesized and their photocatalytic activity was investigated under visible light irradiation using the RhB dye as model pollutant molecule in an aqueous solution. The effect of the amount of BiVO 4 as visible light sensitizer on the photocatalytic activity of BiVO 4 /3DOM TiO 2 nanocomposites was highlighted. The heterostructured composite system leads to much higher photocatalytic efficiencies than bare 3DOM TiO 2 and BiVO 4 nanoparticles. As the proportion of BiVO 4 in BiVO 4 /3DOM TiO 2 nanocomposites increases from 0.04 to 0.6, the photocatalytic performance of the BiVO 4 /3DOM TiO 2 nanocomposites increases and then decreases after reaching a maximum at 0.2. This improvement in photocatalytic perfomance is related to 1) the interfacial electron transfer efficiency between the coupled materials, 2) the 3DOM TiO 2 inverse opal structure with interconnected pores providing an easy mass transfer of the reactant molecules and high accessibility to the active sites and large surface area and 3) the effect of light sensitizer of BiVO 4 . Intensive studies on structural, textural, optical and surface properties reveal that the electronic interactions between BiVO 4 and TiO 2 lead to an improved charge separation of the coupled BiVO 4 /TiO 2 system. The photogenerated charge carrier densities increase with increasing the BiVO 4 content, which acts as visible light sensitizer to the TiO 2 and is responsible for the enhancement in the rate of photocatalytic degradation. However, the photocatalytic activity is reduced when the BiVO 4 amount is much higher than that of 3DOM TiO 2 . Two reasons could account for this behavior. First, with increasing BiVO 4 content, the photogenerated electron/hole pairs are accumulated at the surface of the BiVO 4 nanoparticles and the recombination rate increases as shown by the PL results. Second, decreasing the amount of 3DOM TiO 2 in the nanocomposite decreases the surface area as shown by the BET results. Mo...

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“…The band-gap energy can therefore be estimated from the intercept of the plots of (αhν) 1/2 versus (hν) as illustrated in Fig. 7 [60]. Fig.…”

Section: Optical Propertiesmentioning

confidence: 99%

BiVO4/3DOM TiO2 nanocomposites: Effect of BiVO4 as highly efficient visible light sensitizer for highly improved visible light photocatalytic activity in the degradation of dye pollutants

Zalfani

et al. 2017

Applied Catalysis B: Environmental

105

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“…Based on the photocatalytic degradation of organic pollutant (OP) in the solution containing γ-Bi2MoO6 (BMO) nanoparticles, a possible mechanism was proposed [47,48] …”

Section: Band Gap Energy (Egmentioning

confidence: 99%

Synthesis of g-Bi2MoO6 by Co-precipitation Method and Evaluation for Photocatalytic Degradation of Rhodamine B, Crystal Violet and Orange II Dyes Under Visible Light Irradiation

Banavatu¹,

Rao²,

Basavaiah³

2017

Asian J. Chem.

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γ-Bismuth molybdate (γ-Bi2MoO6) catalyst has been successfully synthesized by co-precipitation method and followed by calcination using stoichiometry ratio of bismuth nitrate, nitric acid, ammonium molybdate as precursor materials. The synthesized γ-Bi2MoO6 nanoparticles characterized by X-ray diffraction for identifying crystalline phases and particle size, Raman spectroscopy identifies active species during the reaction, Fourier transform infrared spectroscopy is to identify adsorbed species and to study the way in which these species are chemisorbed at the surface of the catalyst, UV-visible diffuse reflectance spectroscopy (UV-DRS) revealed for band energy of semiconductors, Field emission scanning electron microscopy (FE-SEM) is to determine morphology and shape of supported particles and Energy dispersive X-ray analysis (EDX) is for elemental analysis of synthesized nanoparticles. The photocatalytic activity of γ− Bi2MoO6 catalyst evaluated using the degradation of Rhodamine-B, Crystal Violet and Orange II dyes under visible light irradiation at room temperature.

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“…Among the three available crystal phases of BiVO 4 , monoclinic BiVO 4 (m-BiVO 4 ) is an important material with many applications. It is a wide band semiconductor with a bandgap of 2.4 eV (≈520 nm) and it exhibits much higher photocatalytic activity with respect to the other polymorphs [24][25][26]. The bandgap of BiVO 4 is around 520 nm (2.4 eV) hence ideally it should have little or no absorption at a wavelength of 800 nm (1.5 eV) pump light.…”

Section: Sample Preparationmentioning

confidence: 99%

Investigation of Terahertz Emission from BiVO4/Au Thin Film Interface

Kumar

Abdi

Trześniewski

et al. 2015

J Infrared Milli Terahz Waves

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One-Pot Template-Free Hydrothermal Synthesis of Monoclinic Hollow Microspheres and Their Enhanced Visible-Light Photocatalytic Activity

Cited by 26 publications

References 59 publications

BiVO4/3DOM TiO2 nanocomposites: Effect of BiVO4 as highly efficient visible light sensitizer for highly improved visible light photocatalytic activity in the degradation of dye pollutants

BiVO4/3DOM TiO2 nanocomposites: Effect of BiVO4 as highly efficient visible light sensitizer for highly improved visible light photocatalytic activity in the degradation of dye pollutants

Synthesis of g-Bi2MoO6 by Co-precipitation Method and Evaluation for Photocatalytic Degradation of Rhodamine B, Crystal Violet and Orange II Dyes Under Visible Light Irradiation

Investigation of Terahertz Emission from BiVO4/Au Thin Film Interface

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