This review covers the major reactions involved in the solution synthesis of nanomaterials.It was designed to classify the traditional strategies such as precipitation,reduction,seed growth,etching,and so on into two basic processes which are termed as bottom-up and top-down routines.The discussion is focused on the basic mechanism and principles during the nudeation and growth of nanocrystals,especially in the solution system.This review also presents a prediction for how to utilize these intrinsic processes to artificially construct the desired specific and functional nanostructures.We try to describe the most directive and effective way to control the structures of nanocrystals for researchers who can master the major reaction mechanism and grasp the basic technologies in synthetic nanoscience.
Two-dimensional nanomaterials （2DNMs） have attracted increasing attention due to their unique properties and promising applications. Unlike 2DNMs with lamellar structures, metal ultrathin 2DNMs are difficult to synthesize and stabilize because they tend to form close-packed crystal structures. Most reported cases consist of monometallic and heterogeneous nanostructures. The synthesis of metal alloy 2DNMs has been rarely reported. Here, we report the synthesis of PdNi alloy wavy nanosheets （WNSs） using an enhanced CO-confinement strategy. This strategy is also suitable to the synthesis of other Pd-based alloy WNSs such as PdCu, PdFe, and even a trimetallic PdFeNi.
Weng-Chon Cheong Chuhao Liu Menglei Jiang Haohong Duan Dingsheng Wang Chen Chen Yadong Li
Multi-shelled CoFe2O4 hollow microspheres with a tunable number of layers （1-4） were successfully synthesized via a facile one-step method using cyclodextrin as a template, followed by calcination. The structural features, including the shell number and shell porosity, were controlled by adjusting the synthesis parameters to produce hollow spheres with excellent capacity and durability. This is a straightforward and general strategy for fabricating metal oxide or bimetallic metal oxide hollow microspheres with a tunable number of shells.
A novel one-pot approach to synthesize the tiara-like Pd(II) thiolate complex compound, [Pd(SCH_3)_2]_6, was developed. In this strategy, dimethyl sulfoxide(DMSO) was used as a thiolate source instead of methyl mercaptan(CH_3SH). DMSO was first decomposed into CH_3SH and formaldehyde(HCHO); then, the in situ as-formed CH_3SH molecules reacted with palladium acetate, and formed [Pd(SCH_3)_2]_6. By tuning the reaction condition, the morphology of the [Pd(SCH_3)_2]_6 assemblies can change from microprism to nanosphere. The characterization of the pyrolysis product demonstrated that these two kinds of [Pd(SCH_3)_2]_6 assemblies with different shapes could further decompose into palladium or palladium sulfides through different pyrolysis conditions.
In this work, ultra-large sheet NiAl-layered double hydroxide(LDH)/reduced graphene oxide(RGO) nanocomposites were facilely synthesized via in situ growth of NiAl-LDH on a graphene surface without any surfactant or template. It was found that with a microwave-assisted method, NiAl-LDH nanosheets grew evenly on the surface of graphene. With this method, the formation of NiAl-LDH and reduction of graphene oxide were achieved in one step. The unique structure endows the electrode materials with a higher specific surface area, which is favorable for enhancing the capacity performance. The morphology and microstructure of the as-prepared composites were characterized by X-ray diffraction, Brunauer-EmmettTeller surface area measurement, and transmission electron microscopy. The specific surface area and pore volume of the RGO/LDH composite are 108.3 m^2 g^(-1) and 0.74 cm^3 g^(-1), respectively, which are much larger than those of pure LDHs(19.8 m^2 g^(-1) and 0.065 cm^3 g(-1), respectively). The capacitive properties of the synthesized electrodes were studied using cyclic voltammetry and electrochemical impedance spectroscopy in a three-electrode experimental setup. The specific capacitance of RGO/LDHs was calculated to be 1055 F g^(-1) at 1 Ag^(-1). It could be anticipated that the synthesized electrodes will find promising applications as novel electrode materials in supercapacitors and other devices because of their outstanding characteristics of controllable capacitance and facile synthesis.
