Search

Abstract: Bimetallic nanomaterials consisting of magnetic metals and noble metals have attracted much interest for their promising potentials in fields such as magnetic sensors, catalysts, optical detection and biomedical applications. Bimetallic nanomaterials synthesized by wet-chemical methods with different architectures including nanoparticles, nanowires or nanotubes and their assemblies are summarized in this review. The particular properties of bimetallic nanomaterials, especially their magnetic, catalytic and optical properties, are presented. The advance in electron microscopy makes it possible to understand the nanostructural materials at much higher level than before, which helps to disclose the relationship between the microstructures and properties qualitatively and quantitatively. [Copyright &y& Elsevier]

Two-dimensional (2D) layered materials are assembled through the intralayer covalent bonds and interlayer van der Waals (vdWs) interactions. The relatively weak interlayer vdWs interactions result in the weak interlayer mechanical coupling between layers, which strongly impacts the overall mechanical properties of multilayer 2D materials or heterostructures. Experimentally probing the interlayer mechanical coupling is of vital importance on the accumulation of fundamental parameters for their applications in flexible and stretchable devices, yet there are hardly comprehensive reviews in this research field. In this review, we firstly introduce the probing methods of interlayer mechanical coupling, including high-frequency and ultralow-frequency Raman characterizations, nanoindentation of multilayer 2D materials or heterostructures, surface indentation, pressurized blister test, characterization of spontaneously formed nanoblisters, and nano-friction tests. Based on the analysis and comparison of the existing methods and results, we also discuss the advantages and limitations of each method. Finally, the challenges and opportunities in this promising field are discussed. This review summarizes the recent progress in the probing of interlayer mechanical coupling of 2D layered materials and will provide important reference for the rational design of flexible and stretchable devices. [Display omitted] • The interlayer interactions strongly impact the mechanical properties of multilayer 2D materials or heterostructures. • Probing the interlayer mechanical coupling of 2D materials is very important for the accumulation of fundamental parameters. • The current experimental methods of probing the interlayer mechanical coupling of 2D layered materials are summarized. [ABSTRACT FROM AUTHOR]

Metal-semiconductor heterostructure nanoparticles (NPs) have attracted much interest and extensively been investigated due to their promising potentials in the fields of catalysis, energy conversion and storage. Due to the synergistic effect and coupling effect between metal and semiconductor, designing and controlling the interface structure of metal-semiconductor NPs and understanding the structure-property relationship have great significance for optimizing their physicochemical performances. Metal NPs coupled with semiconductors forming several kinds of interface structures, including core-shell, yolk-shell, Janus and oligomer-like structures are summarized in this review. The controllable synthesis methods to obtain metal-semiconductor heterostructure NPs with fantastic properties are presented in detail. Moreover, the structure-property relationship and their applications in the fields of catalysis, energy conversion and storage are also exhibited. A brief outlook is given on the challenges and possible solutions in future development of metal-semiconductor NPs. Image 1 • Forming metal-semiconductor heterostructure is an effective way to improve the properties of semiconductor materials. • Structure design and controllable synthesis methods for metal-semiconductor heterostructure nanoparticles are summarized. • The interface structure of metal-semiconductor nanoparticles is a key factor that influence their performances. [ABSTRACT FROM AUTHOR]

Cu 2 O is an ideal template material for the preparation of transition metal hydroxide/oxyhydroxides with oxygen evolution reaction (OER) enhanced catalytic performance. Here, inspired by Pearson's principle, Cu 2 O wires were prepared and used as a sacrificial template to prepare Ni(OH) 2 ·0.75H 2 O hollow tubes (Ni(OH) 2 HTs) with highly improved surface roughness. Benefiting from unique structural advantages, the Ni(OH) 2 HTs showed excellent catalytic activity, rapid kinetics and a long-term stability as the OER catalyst, where an overpotential of only 207 ​mV was required to drive a current density of 10 ​mA ​cm−2, an ideal kinetics with a Tafel slope as 79.8 ​mV dec−1 was calculated, and no obvious attenuation in chronoamperometry was discovered after operation for 24 ​h. This paper provides a novel template-assisted strategy to prepare high-performance transition metal-based OER catalysts possessing hollow and tubular structures. [Display omitted] • For the first time , we used Cu 2 O wires as hard template to prepare hollow tubular Ni(OH) 2. • The Ni(OH) 2 HTs possess novel morphologies with stable hollow one-dimensional structure and rough surface. • As OER catalyst, the Ni(OH) 2 HTs showed excellent electrochemical performances for overpotential, kinetics and stability. [ABSTRACT FROM AUTHOR]

There is currently intense interest in the use of nanoparticles for a wide range of biomedical and technological applications. In this paper, the hierarchical Co doped ZnO nanoflowers were synthesized by a facile wet chemical method and explored as biosensing material. The as-modified novel hydrogen peroxide sensor exhibited a wide linear range (0.25–20 mM), highly reproducible response (R.S.D. of 2.7%) and long-term stability. The doping Co 2+ ions carried out the oxidations rapidly and efficiently for the catalysis of hydrogen peroxide (H 2 O 2 ). A high activity toward H 2 O 2 in the presence of ascorbic acid (AA) and NaNO 2 , which are only common for natural enzymes, has also been demonstrated. The good analytical performance, low cost and straightforward preparation method makes this doped semiconductor promising for a wide range of potential applications in medicine, biotechnology and environmental chemistry. [ABSTRACT FROM AUTHOR]

Both α-Co(OH) 2 and Co 3 O 4 porous microspheres have been synthesized by the simple solvothermal process as well as subsequent treatment. The morphologies and structures of the as-synthesized products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). Both samples have spherical structures consisting of nanosheets, with similar crystallinity. The electrochemical properties of both samples were further investigated. Both samples show excellent electrochemical performances including high specific capacity, good cycling stability and rate capability. All results show that these microspheres exhibit potential applications in energy storage field. [ABSTRACT FROM AUTHOR]

Noble metal-semiconductor hybrids have been employed as fundamental structures in modern technologies. In these hybrids, their cooperative multiple functions attract much attention in recent years because of the interplay of nanoparticles and nanostructures. In this review, we summarize the interplay of nanoparticles and nanostructures in specific kinds of noble metal-semiconductor hybrids, termed as non-symmetric hybrids of noble metal-semiconductor. It particularly refers to metal nanoparticles (or semiconducting quantum dots) at 1-dimensinal (1D) and 2-dimensional (2D) semiconductor (or metal) nanostructures, in contrast to the core/shell and heterodimer nanostructures. First, we discuss the formation dynamics, especially in chemical growth and assembly as well as physical coating and deposition, of non-symmetric noble metal-semiconductor hybrids with nanoparticles on nanostructures. Second, we introduce the plasmon-related applications of these hybrids in heterogeneous catalysis, optoelectronic or photovoltaic devices, all-optical devices, and surface detection or modulation. This review not only provides a comprehensive understanding of the formation mechanisms of the non-symmetric metal-semiconductor hybrid nanostructures, but also may inspire new ideas of novel functional devices and applications based on these systems. [ABSTRACT FROM AUTHOR]

Abstract: Nearly monodispersed hollow nanospheres of bimetallic NiPt have been synthesized by a one-pot wet chemical method at room temperature with a precursor Ni nanocompound as a sacrificial template. The size control is carried out via the sacrificial template, from about 35nm to nearly 100nm in diameter. The shell thickness of the NiPt hollow sphere reaches down to as thin as 2–3nm slightly larger than a single layer of alloyed NiPt nanocrystallites. The product with the citric acid as surfactant exhibits enhanced oxygen reduction activities compared to a commercial Pt/C catalyst and the hollow nanospheres coated with PVP. It has potential applications in fuel cells, biotechnology and environmental chemistry with the facile synthesis, low cost and excellent electrocatalytic activity. [Copyright &y& Elsevier]

Abstract: This paper reports that the high pressure in situ angle dispersive x-ray diffraction and Raman scattering studies on CoPt and NiPt hollow nanospheres are performed by means of a diamond anvil cell for generating external pressure at room temperature. The crystal structures of both the CoPt and NiP hollow nanospheres keep stable up to about 41GPa. Moreover, it shows that the hollow nanospheres possess higher bulk moduli than their bulk counterparts by using the first-principles density functional theory. [Copyright &y& Elsevier]