Microwave-assisted synthesis of bismuth oxide

Abstract

Single phase and ultrafine bismuth oxide was synthesized via microwave-assisted hydrothermal synthesis. The effect of reaction parameters (temperature/pressure and pH) on the product phase composition and morphology was discussed. The transformation of bismuth hydroxide into bismuth oxide was controlled by pH value and it was accelerated by time and temperature. The phase composition of reaction products was strongly dependent on pH value. The amorphous products were obtained at acidic pH conditions and the crystalline single phase product ?-Bi2O3 phase was obtained at pH ?12. The particle size was reduced from micrometric to nanometric size in the presence of a chelating agent. The bismuth hydroxides into bismuth oxides transformation mechanism, consisting in polycondensation of Bi - OH bounds to Bi-O-Bi bridges and crystallization of Bi2O3, was proposed.

The Role of H2C2O4 and Na2CO3 as Precipitating Agents on The Physichochemical Properties and Photocatalytic Activity of Bismuth Oxide

“…Below is the revised figure 1 Figure 3. The result of FTIR analysis on synthesized bismuth oxide showed that both samples showed the vibrational band at 845 cm -1 indicating the presence of Bi-O-Bi [15]. Futhermore, both samples also showed the vibrational band at 1384 cm -1 indicating the vibration of Bi-O stretching [16].…”

Hydrazine and Urea Fueled-Solution Combustion Method for Bi2O3 Synthesis: Characterization of Physicochemical Properties and Photocatalytic Activity

“…FTIR spectra of both products before and after calcination are presented in Figure 3. FTIR spectra before calcination for Bi2O3 fuelled by urea and hydrazine formed successive peaks at wavenumbers 813 and 811 cm -1 which indicate the existence of a Bi-O-Bi group [30] and peaks at wavenumber 1300 cm -1 which implies Bi-O group. Furthermore, synthesized Bi2O3 with urea and hydrazine fuels formed peaks at wavenumbers 1035 and 1034 cm -1 which are N-H bending vibrations [31].…”

“…Furthermore, synthesized Bi2O3 with urea and hydrazine fuels formed peaks at wavenumbers 1035 and 1034 cm -1 which are N-H bending vibrations [31]. Meanwhile, after calcination, FTIR spectra for Bi2O3 with urea (BO1) and hydrazine (BO2) generated peaks at wavenumbers 841 and 847 cm -1 which indicate the existence of a Bi-O-Bi group [30] and peaks at wavenumbers 1397 and 1377 cm -1 which specify the Bi-O (b) (a) group [32]. The vibration mode of the two products is the same as the vibration mode of pure bismuth oxide.…”

Deviations from Vegard's Law and Intense Raman Scattering in Low‐Doped Bi2Mo1−xWxO6 (x = 0–10%) Ceramics

“…Typical pellet surface of Bi 2 MoO 6 composition is shown in Figure a using field‐emission scanning electron microscopy (SEM) image post hydraulic compaction and microwave sintering at 595 °C for 2 h. An interesting hexagonal grain formation with alternately arranged equal dimensions is an excellent manifestation of equilibrium thermodynamics behind triple lines expected in nanomaterials . Such a continuous grain formation occurs in powders with schematically distributed pores usually derived in microwave synthesis . All grains have edge‐to‐edge dimensions of 1.8 μm, which is very well below the known standard range (2–10 μm) of grain size in bismuth layer materials.…”