Synthesis, structural characterization, and photocatalytic activity of Bi‐based nanoparticles

Abstract

Bi‐based nanoparticles were successfully synthesized (500°C/2 h) following two intermediate‐temperature routes, Pechini and a combined method of mechanical milling/molten salts. Herein, α‐Bi2O3/Bi2O2CO3 heterostructures were identified. These types of heterostructures have shown advantages to improve the visible light responsive activity of Bi‐based nanoparticles to facilitate the separation of photogenerated electron‐hole pairs. By fixing the experimental parameters, the synthesis route and Ag contents showed to play a very important role in the phase composition of the Ag‐containing samples; the formation of Bi/Ag‐Bi2O3/Bi2O2CO3 and Ag/Ag‐Bi2O3/Bi2O2CO3 complex hybrid structures were revealed. The α‐Bi2O3/Bi2O2CO3 heterostructure prepared by combined method exhibited higher photocatalytic efficiency (66.84%) for degrading methylene blue (MB) depending on Bi2O2CO3 component proportion. For the Ag‐containing hybrid structures, the performance of their catalytic activity did not show an increase with respect to α‐Bi2O3/Bi2O2CO3. However, in these samples, the degradation efficiency was slightly enhanced with the efficient doping of Ag into the α‐Bi2O3 structure and the existence of Bi when the Pechini method was used. Also, a possible photocatalytic process for degrading MB is presented.

Toward Expanding the Optical Response of Ag2CrO4 and Bi2O3 by Their Laser-Mediated Heterojunction

“…In the case of sample B, even when the specimen is composed by a mixture of α-Bi 2 O 3 with the symmetry space group P2 1 /c, δ-Bi 2 O 3 Pn3̅ m, and Bi 2 O 2 CO 3 Pna2 1 , it is possible to clearly identify only 11 out of the 30 Raman-active modes of α-Bi 2 O 3 , 15A g + 15B g , which is typical when the Raman spectrum of α-Bi 2 O 3 plus additional bismuth oxides derivatives is taken at room temperature. 34,35 The identified modes located below 120 cm −1 belong to the vibration of Bi atoms (Bi−Bi), the ones found in the 120−150 cm −1 region belong to the vibrations of the Bi and O atoms (Bi−O), and those above 150 cm −1 belong to the vibrations of the O atoms (O− O). 36 The irradiated sample (B (F)) shows the same peaks but broadened, giving the impression that the near peaks combine.…”

Structural, Optical and Photocatalytic Activity of Multi-heterojunction Bi2O3/Bi2O2CO3/(BiO)4CO3(OH)2 Nanoflakes Synthesized via Submerged DC Electrical Discharge in Urea Solution

“…The structure of Bi 2 O 2 CO 3 is composed of(Bi 2 O 2 ) 2+ slabs that are intertwined by means of CO 3 2− layers, which lead to a large IEF and improved photocatalytic performance [26,43]. However, the photocatalytic application of Bi 2 O 2 CO 3 under the solar spectrum is limited due to the wide band gap between 2.8 and 3.5 eV and low charge separation efficiency [26,43,44]. Hence, the formation of junctions between Bi 2 O 2 CO 3 and other visible responsive photocatalytic semiconductors like α-Bi 2 O 3 is an appropriate way to extend the photocatalytic activity even under visible light, such as α-Bi 2 O 3 /Bi 2 O 2 CO 3 and Bi 2 O 2 CO 3 /Bi 2 S 3 , Bi 2 O 2 CO 3 / BiOCl [44,45,46].…”

Structural, Optical and Photocatalytic Activity of α-Bi2O3/Bi2O2CO3/(BiO)4CO3(OH)2 Ternary Multi-heterojunction Nanoflakes Synthesized via Submerged DC Electrical Discharge in Urea Solution

“…The structure of (BiO) 2 CO 3 is composed of (Bi 2 O 2 ) 2+ slabs that are intertwined by means of CO 3 2− layers, which lead to IEF and improve photocatalytic performance 25,39 . However, the photocatalytic application of (BiO) 2 CO 3 under the solar spectrum is limited due to the wider band gap between 2.8 eV and 3.5 eV and lower charge separation e ciency 25,39,40 preparation by one-pot in-situ growth were reported elsewhere 25,39,45−48 . Compared with several conventional techniques for nanostructures synthesis, DC electrical arc discharge in liquid provides a straightforward, exible and cost-effective method for mass production nanomaterials without environmental footprints.…”