Self-Assembled Growth of Hollow Spheres with Octahedron-like Co Nanocrystals via One-Pot Solution Fabrication

Abstract

In this work, we report a simple one-pot approach to prepare hollow Co microspheres via self-assembly of octahedron-like nanocrystals. Uniform hollow Co spherical assemblies, prepared via a facile solvothermal reduction approach in the presence of NaCl, were composed of ordered nanooctahedra with a thickness of about 80–120 nm. The formation mechanism (NaCl-assisted Ostwald ripening) has been investigated with TEM/HRTEM/SEM/XRD methods. Surface morphologies of Co hollow spheres have been finely modulated from rough to smooth surface through altering reaction conditions (such as time, temperature, and amount of NaCl). The interior-cavity size of the Co hollow sphere has been well tunable by controlling reaction time or temperature. These materials exhibit good ferromagnetic characteristics, showing their potential applications for catalysts and other related devices. The influence of surface morphology, the interior cavity size, and surface modification upon the magnetic properties of hollow Co spheres have been systematically studied. The possible reasons for diverse magnetic properties of products obtained under different conditions are also discussed.

Low-temperature template-free synthesis of Cu2O hollow spheres

“…Recently, similar mechanisms have been used to prepare Fe 3 O 4 , Co, CdIn 2 S 4 , a-MnO 2 , rare earth phosphate, and magnetic hybrid copolymer-cobalt hollow spheres [52][53][54][55][56][57]. The possible formation mechanism of hollow sphere is shown by the schematic diagram in Fig.…”

Room-temperature synthesis of air stable cobalt nanoparticles and their use as catalyst for methyl orange dye degradation

“…In recent years several wet-chemical approaches such as pyrolysis [1,2], solvothermal [3], hydrothermal decomposition [4], modified polyol processes [5] and template-based methods [6] have been developed to synthesize cobalt crystals with different morphologies. Some efforts have been focused on exploring the relations between their shapes and properties.…”

Complex–Surfactant‐Assisted Hydrothermal Synthesis and Properties of Hierarchical Worm‐Like Cobalt Sulfide Microtubes Assembled by Hexagonal Nanoplates

“…Many recent efforts have been devoted to the controllable organization of primary building blocks into hierarchical hollow structures. To date, most reported hierarchical hollow structures are hollow spheres that are assembled from various nanobuilding units, such as nanowires, [4] nanorods, [5] nanobelts, [6] nanoribbons, [7] nanosheets, [8][9][10][11][12] nanocubes, [13,14] octahedron-like nanocrystals, [15] and hollow nanospheres. [16] In addition, hierarchical hollow cages, including rhombododecahedral silver cages, [17] cubic MoS 2 cages, [18] and octahedral and cubic Cu 2Àx Se cages, [19] have been obtained through different strategies.…”