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 Zn<inf>2</inf>Al(OH)<inf>6</inf>(NO<inf>3</inf>)<inf>0.3</inf>(CO<inf>3</inf>)<inf>0.35</inf>{dot operator}xH<inf>2</inf>O primary nanoparticles re-dispersed, but the Zn<inf>2</inf>Al(OH)<inf>6</inf>(NO<inf>3</inf>){dot operator}xH<inf>2</inf>O 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 Zn<inf>2</inf>Al(OH)<inf>6</inf>(NO<inf>3</inf>)<inf>y</inf>(CO<inf>3</inf>)<inf>0.5(1-</inf><inf>y</inf><inf>)</inf>{dot operator}xH<inf>2</inf>O 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 NO<inf>3</inf><sup>-</sup> to CO<inf>3</inf><sup>2-</sup>, monodispersed Zn<inf>2</inf>Al(OH)<inf>6</inf>(NO<inf>3</inf>)<inf>y</inf>(CO<inf>3</inf>)<inf>0.5(1-</inf><inf>y</inf><inf>)</inf>{dot operator}xH<inf>2</inf>O (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

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Nanoparticles
Anions
Negative ions
Surface charge
Coprecipitation
Charge density
Agglomeration
Chemical analysis
Coarsening
Crystallization
hydroxide ion
Phase separation
Nanostructures
Particle size
Crystalline materials
Temperature

Keywords

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

ASJC Scopus subject areas

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

Cite this

@article{a3bc926932624a4ebeefe997b7180e30,
title = "Insights into the synthesis of layered double hydroxide (LDH) nanoparticles: Part 2. Formation mechanisms of LDH",
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.",
keywords = "Controlled synthesis, Formation mechanism, Layered double hydroxide nanoparticle, Phase separation, Surface energy",
author = "Xiaodi Sun and Sandwip Dey",
year = "2015",
month = "11",
day = "5",
doi = "10.1016/j.jcis.2015.06.025",
language = "English (US)",
volume = "458",
pages = "160--168",
journal = "Journal of Colloid and Interface Science",
issn = "0021-9797",
publisher = "Academic Press Inc.",

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TY - JOUR

T1 - Insights into the synthesis of layered double hydroxide (LDH) nanoparticles

T2 - Part 2. Formation mechanisms of LDH

AU - Sun, Xiaodi

AU - Dey, Sandwip

PY - 2015/11/5

Y1 - 2015/11/5

N2 - 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.

AB - 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.

KW - Controlled synthesis

KW - Formation mechanism

KW - Layered double hydroxide nanoparticle

KW - Phase separation

KW - Surface energy

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U2 - 10.1016/j.jcis.2015.06.025

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VL - 458

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JO - Journal of Colloid and Interface Science

JF - Journal of Colloid and Interface Science

SN - 0021-9797

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