Synthesis and growth mechanism of various structures Bi2O3 via chemical precipitate method

Structural and Enhanced Optical Properties of Stabilized γ‒Bi2O3 Nanoparticles: Effect of Oxygen Ion Vacancies

“…Hereof, in recent decades, various physical and chemical methods have been introduced for the synthesis of RT stabilized γ–Bi 2 O 3 nanostructures with various morphologies [ 1 , 9 ]. Versatile forms of nanostructures could be obtained either by heating the mixture at low temperature (40–90 °C) [ 2 , 3 , 24 , 25 , 26 , 27 , 28 , 29 ] or in some methods at high temperature (300–800 °C) [ 4 , 6 , 7 , 30 , 31 , 32 ].…”

“…The synthesis of RT stabilized γ–Bi 2 O 3 through a chemical method is usually sensitive to the preparation conditions such as reaction temperature, time, and additive types [ 4 , 20 , 25 ]. Li et al introduced various surfactants for RT stabilization of γ–Bi 2 O 3 [ 2 ].…”

γ-Bi2O3 – To Be or Not To Be? Comparison of the Sillenite γ-Bi2O3 and Isomorphous Sillenite-Type Bi12SiO20

“…As mentioned at the beginning, metastable γ-Bi 2 O 3 is accessible by cooling from high temperatures; however, within the last decades numerous studies dealing with the synthesis of γ-Bi 2 O 3 by hydrothermal precipitation reactions were reported. − The structure and composition of the as-prepared “γ-Bi 2 O 3 “ was most commonly determined using Powder X-ray Diffraction accompanied by TEM and SEM/EDX analyses. Comparing the several synthetic approaches, a general scheme becomes obvious that is always based on the same steps: the starting material (most often Bi­(NO 3 ) 3 ·5H 2 O − or BiCl 3 ) is dissolved in aqueous media (usually dilute nitric or hydrochloric acid, respectively) followed by adding a surfactant (such as CTAB, , polyethylene glycols, ,,,− ethylene glycol, , or sodium dodecyl sulfate) and aqueous NaOH, ,− KOH, or NH 4 OH solutions.…”

“…As mentioned at the beginning, metastable γ-Bi 2 O 3 is accessible by cooling from high temperatures; however, within the last decades numerous studies dealing with the synthesis of γ-Bi 2 O 3 by hydrothermal precipitation reactions were reported. − The structure and composition of the as-prepared “γ-Bi 2 O 3 “ was most commonly determined using Powder X-ray Diffraction accompanied by TEM and SEM/EDX analyses. Comparing the several synthetic approaches, a general scheme becomes obvious that is always based on the same steps: the starting material (most often Bi­(NO 3 ) 3 ·5H 2 O − or BiCl 3 ) is dissolved in aqueous media (usually dilute nitric or hydrochloric acid, respectively) followed by adding a surfactant (such as CTAB, , polyethylene glycols, ,,,− ethylene glycol, , or sodium dodecyl sulfate) and aqueous NaOH, ,− KOH, or NH 4 OH solutions. After heating the mixture (70–90 °C) − some protocols allude annealing of the products at higher temperatures (500–600 °C) ,, which is unexpected due to studies, that report the phase transition of the metastable γ-Bi 2 O 3 into α-Bi 2 O 3 in this temperature range. ,, However, without exception the successful synthesis of the metastable γ-Bi 2 O 3 is postulated. − It might be noted that the formation of ω-Bi 2 O 3 was also postulated...…”

“…Comparing the several synthetic approaches, a general scheme becomes obvious that is always based on the same steps: the starting material (most often Bi­(NO 3 ) 3 ·5H 2 O − or BiCl 3 ) is dissolved in aqueous media (usually dilute nitric or hydrochloric acid, respectively) followed by adding a surfactant (such as CTAB, , polyethylene glycols, ,,,− ethylene glycol, , or sodium dodecyl sulfate) and aqueous NaOH, ,− KOH, or NH 4 OH solutions. After heating the mixture (70–90 °C) − some protocols allude annealing of the products at higher temperatures (500–600 °C) ,, which is unexpected due to studies, that report the phase transition of the metastable γ-Bi 2 O 3 into α-Bi 2 O 3 in this temperature range. ,, However, without exception the successful synthesis of the metastable γ-Bi 2 O 3 is postulated. − It might be noted that the formation of ω-Bi 2 O 3 was also postulated, although the PXRD pattern of “ω-Bi 2 O 3 ” shows an unexplained mismatch with the cited XRD-file of ω-Bi 2 O 3 (ICDD 00-050-1088) . Noteworthy, ω-Bi 2 O 3 was prepared by Gualtieri et al heating α-Bi 2 O 3 to 800 °C on a BeO substrate which most probably is essential to stabilize this metastable polymorph .…”