Abstract

This study demonstrates the effect of (co)intercalated anion compositions on nanostructure evolution to understand the formation mechanisms of layered double hydroxide (LDH) nanoparticles following coprecipitation and hydrothermal treatments (HT). Initially, the room temperature coprecipitation resulted in amorphous primary nanoparticles that agglomerated at the edges due to low surface charge densities. The reversibility of such agglomeration was determined by the crystalline quality upon HT and consequent surface charge density, which in turn were strongly influenced by the composition of the intercalated anions. Upon crystallization, the agglomerated Zn2Al(OH)6(NO3)0.3(CO3)0.35{dot operator}xH2O primary nanoparticles re-dispersed, but the Zn2Al(OH)6(NO3){dot operator}xH2O nanoparticles with much lower stability and higher disorder (especially at the edges) exhibited irreversible agglomeration, and transformed into secondary nanoparticles via aggregational growth. Additionally, the stability studies on Zn2Al(OH)6(NO3)y(CO3)0.5(1-y){dot operator}xH2O nanoparticles (y=0-1) showed that the size difference between the cointercalated anions caused phase separation when 0.9≥y≥0.6, leading to bimodal size distributions. Moreover, the coarsening rates were controlled through the cointercalated anion compositions. By gradually varying the ratio of cointercalated NO3- to CO32-, monodispersed Zn2Al(OH)6(NO3)y(CO3)0.5(1-y){dot operator}xH2O (0.5≥y≥0) nanoparticles with systematic variation in the particle size of ~200-400nm were obtained after HT at 85°C for 12h.

Original languageEnglish (US)
Pages (from-to)160-168
Number of pages9
JournalJournal of Colloid And Interface Science
Volume458
DOIs
StatePublished - Nov 5 2015

Keywords

  • Controlled synthesis
  • Formation mechanism
  • Layered double hydroxide nanoparticle
  • Phase separation
  • Surface energy

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Surfaces, Coatings and Films
  • Colloid and Surface Chemistry

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