JOURNAL OF RARE EARTHS, Vol. 35, No. 5, May 2017, P. 474 Foundation item: Project supported by DST (SB/S1/PC-08/2012), Govt. of India and University of Delhi under the “Scheme to Strengthen R&D Doctoral Research Program” and DU-DST PURSE Grant * Corresponding author: Rajamani Nagarajan (E-mail: rnagarajan@chemistry.du.ac.in; Tel.: +91-11-27662650) DOI: 10.1016/S1002-0721(17)60936-0 Facile synthesis and characterization of acetate intercalated Co-La layered double hydroxide Meenakshi Pokhriyal, Sitharaman Uma, Rajamani Nagarajan * (Materials Chemistry Group, Department of Chemistry, University of Delhi, Delhi 110007, India) Received 26 July 2016; revised 25 November 2016 Abstract: Layered double hydroxide (LDH) comprising of Co 2+ and La 3+ -ions with acetate counter anion was successfully synthe- sized by hydrogen peroxide catalyzed hydrolysis reaction and characterized extensively. The observed reflections in the powder X-ray diffraction pattern could be indexed in 3 P space group with a=0.316 nm and c=2.97 nm. Lattice fringes of distances corresponding to the peaks observed in X-ray diffraction pattern were observed in high resolution transmission electron microscopic images. UV-visible diffuse reflectance spectroscopy results confirmed the presence of Co(OH) 6 along with the presence of charge-transfer band due to the interlayer carboxylate anion. Magnetization measurements at room temperature indicated high spin configuration of Co 2+ -ion in the sample exhibiting paramagnetic behavior. The mixed metal oxide from calcination was used to reconstruct the parent layered structure. Intercalation experiments with other organic anions in Co-La LDH proved be successful. Keywords: layered double hydroxides; chemical synthesis; X-ray diffraction; intercalation; organic-inorganic hybrids; rare earths Inorganic lamellar solids exist in many forms and are widely investigated owing to superior application possi- bilities for the betterment of society in areas such as en- vironment, health, and information technologies [1–7] . Lay- ered double hydroxides (LDHs) are a unique class of multifunctional materials and are extensively researched due to their ease of synthesis and stability. They exhibit a broad spectrum of applications originating mainly from the flexibility of the choice of metal cations and rich in- tercalation chemistry [1–9] . They are represented by the general formula [M 2+ 1–x M 3+ x (OH) 2 ][A n– x/n ]·mH 2 O where M 2+ and M 3+ are divalent and trivalent cations, respec- tively; x is equal to the ratio M 3+ /(M 2+ +M 3+ ), A is an an- ion of valence n. The structure of LDHs can be described starting with the brucite-like structure, M(OH) 2 , wherein M 2+ -ions are surrounded by the hydroxide ions in an oc- tahedral fashion sharing edges to form infinite charge neutral layers. Isomorphous replacement of fraction of the divalent cations with a trivalent cation in such bru- cite-based LDHs creates excess positive charge on the layers, counter balanced by the presence of inter layer, (exchangeable) anions. Cobalt containing layered hydroxides and oxides has been used for several catalytic applications such as hy- droxylation of phenol, Fischer-Tropsch catalysts and steam reform of methanol [10–13] . Additionally, when com- bined with the strong and intrinsically basic lanthanum ions, one can multiply the catalytic functions of such systems. Recently published work on the efficient cata- lytic role of calcined oxides from multicationic Mg/Al/ Me LDHs (Me=Y, Dy, Gd, Sm and La) for the highly demanding isomerization reaction of 2,3-dimethyl-1- butene illustrates the need for the generation of lantha- nide incorporated hydroxides [14] . Combined with the electro active and magnetic cobalt ions being part of the lamellar structure, one can efficiently explore electro ca- talysis of many industrially important reactions with the ease of removing the catalysts simply by the application of magnetic field [15–17] . The significance of incorporating cobalt ions in LDHs to act as cellular delivery carriers for the anionic drug molecules due to the overall negative charge of plasma membrane has been elaborated very recently [18] . With all these facts in mind, our aim was to explore a reliable method of holding these two techno- logically significant metal ions in a layered double hy- droxide arrangement. Towards this objective, hydrogen peroxide catalyzed room temperature hydrolysis of ace- tate salts of cobalt and lanthanum has been carried out along with the characterization of product from it using an array of analytical techniques. It is noteworthy that layered salts of zinc, nickel and cobalt have been re- ported earlier by the polyol hydrolysis process without the requirement of any base as precipitating agent [19] . Acetate anion also preserves layered arrangements in rare earth hydroxide salts [20] . The intercalation ability of the acetate containing Co-La LDH with other organic