Halogen-directed nucleation and growth of Bi2O3 columnar hierarchitectures

• Bi2O3 columns were synthesized by introducing Clˉ to the reaction system.
• Formation of the intermediate BiOCl adjusted the Bi2O3 nuclei and growth rate.
• It is Clˉ not CAT+ of CATC that mainly influenced the formation of Bi2O3 columns.

It is generally believed that the positive ions of surfactants such as cetyltrimethylammonium bromide (CTAB) and chloride (CTAC) play a key role in controlling morphology and size of the nanocrystals. Herein, we found that it was negative ions that mainly affected the morphology of α-Bi2O3. The well-crystalline Bi2O3 columnar hierarchitectures assembled by highly-aligned nanorods have been synthesized from the reaction of bismuth citrate and KOH aqueous solution at room temperature with the assistance of halogen ions like Cl− or Br−, whether they came from inorganic salts MX (M = Na+, K+ or NH4+; X = Cl− or Br−) or surfactants CTAX. The formation mechanism of columnar α-Bi2O3 microstructures in the presence of halogen ions was discussed by adjusting the experimental parameters such as NaCl concentration, pH values and so on. The as-prepared Bi2O3 columns exhibited enhanced photocatalytic activity for Rhodamine (RhB) degradation under visible light than scattered Bi2O3 microrods.

Columnar Bi2O3 hierarchitectures with better photoreactivity over scattered rods were prepared by introducing into halogen ions.Figure optionsDownload as PowerPoint slide