Insights into the synthesis of layered double hydroxide (LDH) nanoparticles: Part 2. Formation mechanisms of LDH

JOURNAL OF COLLOID AND INTERFACE SCIENCE

卷:458

Article

Sun, Xiaodi¹  Dey, Sandwip K.^1,2 

[1] Arizona State Univ, Ira A Fulton Coll Engn, Ctr Intervent Biomat, Sch Engn Matter Transport & Energy, Tempe, AZ 85281 USA

[2] Arizona State Univ, Ira A Fulton Coll Engn, Sch Elect Comp & Energy Engn, Tempe, AZ 85281 USA

关键词: Layered double hydroxide nanoparticle;    Formation mechanism;    Controlled synthesis;    Surface energy;    Phase separation;   

DOI  :  10.1016/j.jcis.2015.06.025

来源: Elsevier

【 摘 要 】

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).xH(2)O primary nanoparticles re-dispersed, but the Zn2Al(OH)(6)(NO3).xH(2)O nanoparticles with much lower stability and higher disorder (especially at the edges) exhibited irreversible agglomeration, and transformed into secondary nanopartidies via aggregational growth. Additionally, the stability studies on Zn2Al(OH)(6)(NO3)(6)(CO3)(0.51(1-y)).xH(2)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 to CO, monodispersed Zn2Al(OH)(6)(NO3)(y)(CO3)(0.5(1-y)).xH(2)O (0.5 >= y >= 0) nanoparticles with systematic variation in the particle size of similar to 200-400 nm were obtained after HT at 85 degrees C for 12 h. (C) 2015 Elsevier Inc. All rights reserved.

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