Facile and Controlled Synthesis of 3D Nanorods-Based Urchinlike and Nanosheets-Based Flowerlike Cobalt Basic Salt Nanostructures

Abstract

We report the controlled synthesis of four kinds of cobalt basic salts with different morphologies and colors (pink, blue, green, and lavender) using urea as a hydrolysis agent in the presence of block copolymer P123. Li 2 SO 4 and LiCl were used as salt additives to control the type of cobalt basic salts. It was found that the amount of urea plays a critical role in the synthesis of cobalt basic salts with different phases. Two of them exhibit interesting three-dimensional urchinlike and flowerlike morphology assembled from nanorods (pink) and nanosheets (blue), respectively. The present work suggests that it is possible to directly grow threedimensional-ordered assemblies built from one-dimensional or two-dimensional cobalt basic salt nanostructures through a one-step aqueous solution-phase chemical route under controlled conditions.

Synthesis and structural characterization of cobalt hydroxide carbonate nanorods and nanosheets

“…The band at 971 cm −1 is ascribed to ı(Co-OH) bending modes while the band at 511 cm −1 is ascribed to w (Co-OH) [12]. In addition, the bands observed in the spectra of precursor B at 1504 cm −1 , 1394 cm −1 , 1045 cm −1 , 830 cm −1 , 748 cm −1 and 683 cm −1 , 528 cm −1 , 447cm −1 are attributed to CO 3 2− and Co-O, respectively [9,12]. On the other hand, absorptions of Cl − , NO 3 − , NH 3 or NH 4 + , and NCO − or CN − are not detected.…”

“…ions due to the metal-OH layer and/or water in the crystal [12]. Similarly, a shoulder at around 2927 cm −1 from hydrogen bonding in the interlayer indicates the presence of interlayer water molecules in precursor B, but the precursor A does not show this absorption [9]. The ı(HOH) mode water is also observed at 1646 cm −1 [13].…”

“…Metal hydroxide compounds, expressed using a general formula of M x (OH) y (X) z ·nH 2 O (M: metal, X: anion), are known as layered hydroxide metal salts (LHMS). Firstly, the morphology of the precursor may be effectively controlled by adjusting the interaction between the positively charged layers [M(OH) 2−x ] x+ and anions [9]. Secondly, upon thermal decomposition of the precursor, the metal hydroxide compounds converted into metal oxide by topotactic transformation, the morphology of the metal oxides approximately maintain the morphology of their corresponding precursors.…”

“…Hoson et al [13] fabricated films of brucite-type cobalt hydroxide with nanorod morphology and hydrotalcite-type cobalt hydroxide with nanosheet morphology by heterogeneous nucleation in a chemical bath using water and mixed solution of water-methanol as solvent, respectively. Zhao et al [9] obtained 3D nanorods-based urchinlike and nanosheets-based flowerlike cobalt basic salt nanostructures. At the same time, some reported on the synthesis of cobalt basic salt with the morphology of nanobelts and dandelion by hydrothermal method [14,15].…”

Superior electrochemical properties of spherical-like Co2(OH)3Cl-reduced graphene oxide composite powders with ultrafine nanocrystals

“…The main reduction peaks in the Co 2 (OH) 3 Cl/RGO and CoCl 2 AE6H 2 O/RGO composite powders upon initial discharge were observed at 0.92 and 0.97 V, respectively. Compositionally, Co 2 (OH) 3 Cl is a solid solution of Co(OH) 2 and CoCl 2 [38,48]. Therefore, the reduction peaks correspond to the conversion of Co(OH) 2 and CoCl 2 into Co nanocrystals, LiOH and LiCl, respectively [38,49,50].…”