Layered double hydroxide

1. Layered Double Hydroxide(LDH)
Submitted by
Nabaraj Chetry
Msc 4th Sem
Roll No. 09

2. CONTENTS
Introduction
Synthesis
Characterization
Applications
References

3. INTRODUCTION
Layered double hydroxides , also known as anionic
or hydrotalcite –like clays are a class of lamellar
compounds that consist of positively charged brucite-
like host layers and hydrated exchangeable anions
located in the interlayer gallery for charge balance.
The charge of the brucite like layers arises from the
isomorphous substitution of a part of the divalent
metal ions with trivalent ions.The chemical composi-
tion of LDHs are expressed by the general formula
[MII
1-XMIII
X(OH)2][An-
x/n.mH2O],where MII and MIII
represent di and trivalent metal ions within the brucite
like layers, and An- is an interlayer anion.

4. SYNTHESIS OF LDH
SYNTHESIS OF Co-Al-CO3 LDH
The synthesis was carried out in two neck flask under a nitrogen flow.
CoCl2.6H2O, AlCl3.6H2O and urea were dissolved in 1dm3 of deioni-
zed water.Then, the mixed solution was heated at a refluxing temper-
ature under continuous magnetic stirring for 2 days.The resulting pink,
Solid product was filtered ,washed with deionized water and anhydrous
ethanol several times and finally air dried.

5. CHARACTERIZATION
The XRD pattern of the product that was prepared in CoCl2-AlCl3
urea system is shown in fig 1.

6. Scanning electron microscopy(SEM) images of Co-Al-CO3 LDH
(Low magnification)

7. Scanning electron microscopy (SEM) images of Co-Al-CO3
(High magnification)

8. DECARBONATION & ANION EXCHANGE OF Co-Al LDH.
The deintercalation of carbonate ions from the prepared CO3-LDH was carried
out by treating 1g of LDH into 1dm3 of an aq solution containing 1M NaCl
and 3.3mM HCl.The vessel was sealed after purging with nitrogen gas and
shaken for 12 hrs.The XRD pattern of the sample obtained by this salt- acid
treatment is shown in the figure 3. In this pattern the basal reflections with
d values of 0.75 and 0.375nm for CO3
2- form completely disappeared and a
New series of intense basal reflections appear at lower 2ø angles suggesting
that decarbonation was successful and a high crystalline Cl-- _LDH product
formed.

10. APPLICATIONS OF LDH
 As a catalysts.
As a anion exchanger.
As a acid absorbents.
As a bioactive nano composites.
As a electroactive and photoactive materials.
As a catalyst precursors.

11. REFERENCES
 Synthesis, Anion Exchange, and Delamination of Co-Al L
Hydroxide: Assembly of the Exfoliated Nanosheet/Polya
and Magneto-Optical Studies by
Zhaoping Liu, Renzhi Ma, Minoru Osada,
Nobuo Iyi, Yasuo Ebina, Kazunori Takada, and Takayoshi

12. THANK YOU