A general strategy for synthesis of metal oxide nanoparticles attached on carbon nanomaterials

We report a general strategy for synthesis of a large variety of metal oxide nanoparticles on different carbon nanomaterials (CNMs), including single-walled carbon nanotubes, multi-walled carbon nanotubes, and a few-layer graphene. The approach was based on the π-π interaction between CNMs and modified aromatic organic ligands, which acted as bridges connecting metal ions and CNMs. Our methods can be applicable for a large variety of metal ions, thus offering a great potential application.     

Solution-phase synthesis of monodispersed SnTe nanocrystallites at room temperature

Monodispersed semiconducting SnTe nanocrystallites was successfully prepared via a solution synthesis route at room temperature. It was found that solvent (ethylenediamine), reductant (KBH₄), and tin source (liquid SnCl₄) were crucial factors in the preparation of the titled nanocrystals. X-ray powder diffraction (XRD), transmission electronic microscopy (TEM), X-ray photoelectron spectroscopy (XPS) were used to characterize the product. Raman spectrum of the as-prepared sample had a red shift by five or six wavenumbers in comparison with that of the SnTe single crystals.     

金属氧化物一维纳米材料的制备及其应用

综述了利用阳极氧化铝模板制备金属氧化物一维纳米材料的方法及其在催化剂、光电器件等领域的应用情况,简要指出了尚需进一步研究的问题与发展趋势。     

High photoelectric conversion efficiency of metal phthalocyanine/fullerene heterojunction photovoltaic device

This paper introduces the fundamental physical characteristics of organic photovoltaic (OPV) devices. Photoelectric conversion efficiency is crucial to the evaluation of quality in OPV devices, and enhancing efficiency has been spurring on researchers to seek alternatives to this problem. In this paper, we focus on organic photovoltaic (OPV) devices and review several approaches to enhance the energy conversion efficiency of small molecular heterojunction OPV devices based on an optimal metal-phthalocyanine/fullerene (C(60)) planar heterojunction thin film structure. For the sake of discussion, these mechanisms have been divided into electrical and optical sections: (1) Electrical: Modification on electrodes or active regions to benefit carrier injection, charge transport and exciton dissociation; (2) Optical: Optional architectures or infilling to promote photon confinement and enhance absorption.     

Spherical silica micro/nanomaterials with hierarchical structures: synthesis and applications

This paper reviews the progress made recently in synthesis and applications of spherical silica micro/nanomaterials with multilevel (hierarchical) structures. The spherical silica micro/nanomaterials with hierarchical structures are classified into four main structural categories that include (1) hollow mesoporous spheres, (2) core-in-(hollow porous shell) spheres, (3) hollow spheres with multiple porous shells and (4) hierarchically porous spheres. Due to the complex structures and being focused on spherical silica micro/nanomaterials, some novel methods based on the combination of two routine methods or two surfactants, and some special synthetic strategies are proposed to produce the spherical silica micro/nanomaterials with hierarchical structures. Compared with the same-sized solid, porous or hollow silica spheres, these fantastic spherical silica micro/nanomaterials with hierarchical structures exhibit enhanced properties which may enable them to be used in broad and promising applications as ideal scaffolds (carriers) for biological, medical, and catalytic applications.     

金属硫属化合物纳米材料制备方法的研究进展

金属硫属化合物纳米材料是目前一类非常有发展前途的新材料。本文对金属硫属化合物纳米材料制备方法进行介绍和评述,并提出了它的发展方向。     

Targeted synthesis and environmental applications of oxide nanomaterials

Oxide nanomaterials are indispensable building blocks for a future nanotechnology, because they offer an infinite variety of structural motifs that lead to their widespread technical application. Therefore, flexible and tunable preparative strategies are required to convert this large family of materials onto the nanoscale. Although hydrothermal syntheses have proven especially suitable for this purpose, their reaction pathways and mechanisms often remain unknown so that they can be difficult to control. In the following, we summarize our comprehensive approach towards nanostructured functional oxides that is based on synthetic parameter optimizations, mechanistic in situ investigations and the characterization of environmentally relevant properties, e.g. in photocatalysis or sensor technology. The connection between preparative morphology control and the resulting materials properties is demonstrated for selected tungstate systems and bismuth-containing oxides. Furthermore, different methods for the in situ monitoring of hydrothermal processes are discussed.     

Controlled synthesis of anatase/tungstite heterogeneous nanomaterials induced by oxalic acid

A series of anatase/tungstite heterogeneous nanomaterials with various molar ratios were synthesized by hydrothermal method with oxalic acid as additive, in which the nucleation and growth of tungstite grains were controlled effectively. In our experiments, tungstite grains grew on the surface of TiO₂ grains, which was significant for obtaining heterogeneous composites, and the grain boundaries in composites were considered to promote photocatalytic ability effectively. It was demonstrated that heterogeneous nanomaterials synthesized had obviously better photocatalytic ability than the physical mixture of homogeneous nanomaterials (pure anatase and tungstite) no matter if under ultraviolet irradiation or visible light.     

Hydrothermal synthesis and piezoelectricity of p-SnO nanoparticle/n-ZnSnO3 nanorod array heterojunction films

We investigated the hydrothermal fabrication of n-ZnSnO₃ nanorod array films decorated with various ratios of p-SnO nanoparticles on fluorine-doped tin oxide substrates and their synergistic piezoelectricity-induced applications. We used Mott–Schottky measurements and an energy band diagram to determine the materials’ conductivity type. The associated current–voltage characteristics and charge transport behavior were elucidated by investigating Schottky barriers, Schottky emissions, tunneling, depletion regions, and piezopotential-induced energy band bending. The piezoelectric coefficients (d₃₃) of the ZnSnO₃ nanorod array and the Composite II film were measured to be approximately 15.4 and 17.3 p.m.·V⁻¹, respectively. Theoretical simulation of piezopotential distributions revealed that compressive deformation was predominant for samples under stress. The Composite II film exhibited reliable piezophotodegradation activity for rhodamine B (RhB) solutions, with a degradation rate constant of approximately 1.2 × 10⁻² min⁻¹ under visible-light irradiation, approximately 2.5 times that of the individual ZnSnO₃ film, partially due to intimate contact between the two constitutive components, high electrochemical surface areas, and facilitated charge carrier transport resulting from piezopotential-induced energy band bending. This study revealed the positive effect of piezoelectricity on photodegradation and established a paradigm to allow wide-bandgap materials to function in the visible-light range through a p–n junction.     

Novel approaches to solution-combustion synthesis of nanomaterials

Solution-combustion is an attractive approach to synthesis of nanomaterials for a variety of applications, including catalysts, fuel cells, and biotechnology. In this paper, several novel methods based on the combustion of a reactive solution are presented. These methods include self-propagating sol-gel combustion and combustion of impregnated inert and active supports. It was demonstrated that, based on the fundamental understanding of the considered combustion processes, a variety of extremely high surface area materials could be synthesized. The controlling process parameters are defined and discussed. Examples of materials synthesized by the above methods are presented. For the first time, a continuous technology for production of nanopowders by using the solution combustion approach is demonstrated.      

超临界连续水热法制备无机纳米材料

介绍了超临界连续水热法用于制备无机纳米材料近年来所取得的研究成果。主要介绍了此方法在反应器设计、掺杂型纳米材料的制备及纳米材料的原位改性3方面的研究进展,并对未来的发展进行了展望。     

Solution-combustion synthesis of nanomaterials for lithium storage

Solution-combustion synthesis (SCS) is an effective method for mass production of electrode materials, in particular metal oxides, for electrochemical energy storage owing to its simplicity and energy/time effectiveness. The present mini-review aims at summarizing the recent data on the SCS of nano-structured anode and cathode materials for lithium-ion batteries. The advantages of electrode materials prepared by SCS are discussed in detail, with special emphasis on morphology control during the SCS process.     

水热法制备TiO2一维纳米材料研究进展

TiO2一维纳米材料因其特殊的物理化学性能,在光催化、太阳能电池和传感器等方面受到广泛关注.水热法制备TiO2一维纳米材料具有简单易行、成本低、产率高等优点.本文综述了水热法制备TiO2一维纳米材料过程中原料、反应温度和反应时间、酸洗过程等反应条件对其形貌和晶体结构的影响,探讨了其形成机理及热稳定性,以期为实现TiO2...     

一维贵金属纳米材料的控制合成与应用

一维纳米材料具有优良的尺寸效应,一维贵金属材料表现出不同于相应块体材料的特殊物理化学性能。本文以一维贵金属纳米结构的合成方法和机理为探讨重点,总结了近年来国内外用于控制合成一维贵金属纳米材料的主要方法,包括模板法、多元醇还原法、化学电沉积法以及金属催化还原法。着重以金属银、钯为例,介绍了其形状可控的一维纳米结构的生长机理,并以金、银等一维纳米材料为例介绍了其一维纳米结构在功能材料以及生物医学等领域的应用前景。指出建立一维金属纳米结构制备科学的新理论、新方法及其成核生长动力学模型是进一步研究的方向。     

Supercritical synthesis and characterization of SWNT-based one dimensional nanomaterials

The present study developed a novel, fast and efficient method to synthesize one dimensional nanotube-based materials via supercritical reactions and supercritical fluids. It was proved that supercritical organic fluids were good media to take materials into the nanocavity, not only as solvents but also as reaction agents. Different kinds of metals (Ni, Cu, Ag) and fullerenes (C(60), C(70), C(78), C(84), Gd@C(82), Er@C(82), Ho@C(82), Y@C(82)) were successfully inserted into nanotubes with small diameters by this technique, with various supercritical fluids such as C(2)H(5)OH, CH(3)OH or C(6)H(5)CH(3). The filling rates were proved to be more than 90%. The high filling efficiency and the properties of the as-generated materials were characterized by TEM, Raman, EDS and XPS. In principle, this technique can be applied to construct new types of nanomaterials, if we choose the appropriate supercritical reaction and fluid in the CNTs.     

基于表/界面调控的金属氧化物半导体光催化剂的理性构筑

近年来半导体光催化作为一种绿色技术在解决环境问题和提供可再生能源方面获得了广泛关注,然而较低的催化效率限制着它的实际应用。合理设计金属氧化物半导体的表/界面结构,是提升光催化剂性能的有效手段。对近年来半导体光催化剂的表/界面结构调控以及构-效关系的研究进行了梳理,介绍了在单一组分体系中利用晶面效应优化光催化性能的可行措施。在此基础上,总结了晶面/界面结构调控在复合光催化剂体系中的应用。最后,总结了该领域面临的挑战与未来的前景。     

Ultrasound-assisted synthesis of high-efficiency Ag3PO4/CeO2 heterojunction photocatalyst

The Ag₃PO₄/CeO₂ heterojunction photocatalyst prepared by an ultrasound-assisted method exhibits an enhanced photocatalytic activity compared to pure Ag₃PO₄, CeO₂, and Ag₃PO₄/CeO₂ obtained without ultrasound action. The samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and ultraviolet–visible absorption spectroscopy (UV–vis), and the effects of ultrasound on the physicochemical properties and photocatalytic activity of Ag₃PO₄/CeO₂ are discussed. Results show that the ultrasound-assisted synthesis method significantly improves the photocatalytic ability. The mechanism about the improvement was discussed in details.     

Hydrothermal processing and in situ surface modification of metal oxide nanomaterials

In situ surface modification of TiO₂ and ZnO metal oxide particles has been carried out under hydrothermal conditions within a wide range of temperature and pressure (T = 150–400 °C; P = up to 20 MPa). The influence of the surfactant and selective doping with active metal ions on the crystal size, morphology, and photocatalytic activity of TiO₂ and ZnO particles has been carried out. A systematic characterization of the product has been carried out using powder XRD, FTIR, TGA, SEM/TEM, and UV–vis spectroscopy. Similarly the photocatalytic activity in these metal oxides varies with the size, shape and dopant metals.     

微波辐射应用于合成无机纳米材料的研究进展

对微波辐射合成无机纳米材料的加热原理、促进效应、结构控制等方面的机理进行了探讨,对其无机纳米材料合成的研究进展进行了介绍,并展望了其未来发展方向。