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Porous nanomaterials have attracted extensive interests in adsorption, catalysis, biosensors, and biomedicine due to their high surface area, well-defined pore structure and tunable pore size. However, how to obtain porous nanomaterials of desirable component and unique structure with multifunctionalities and synergetic properties is still a great challenge. In this work, a novel nest-like Ag@mTiO 2 hierarchical nanostructure with Ag nanoparticle as the core and a mesoporous crystalline TiO 2 as the protective shell was successfully prepared by layer-by-layer assembly technique and alkali-etching hydrothermal route. By simply changing the conditions of alkali etching, different nanostructures could be obtained, such as core-shell or rattle type. In the process, the thickness of coating silica layer and TiO 2 shell both played important roles for the formation of desired nanostructures. The as-prepared products had a large specific surface area of 301m 2 /g and a tailored TiO 2 outer shell. Raman spectra results showed perfect SERS signal of the tags enhanced and remained good stability even after one month. Doxycycline (Doxy) was chosen to evaluate their drug loading and controlled release properties. The results indicated that the obtained Ag@mTiO 2 nanoparticles exhibited good biocompatibility and excellent drug-loading capacity. Consequently, they are also expected to serve as ideal candidates for more potential applications including photocatalysis, drug controlled release, biosensor and cell imaging, etc., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Small molecular weight proteins (5.21 kDa) were used as bio-templates to synthesize MnO 2 nanosheets (NSs). This work will open up a protein-directed avenue to synthesize 2D morphology. Further, the as-prepared MnO 2 NSs showed intrinsic peroxidase-like activity and were then applied for glucose detection and evaluation of antioxidant behaviours of typical antioxidants.

In this paper, peapod-like hollow carbon nanomaterial was fabricated via an efficient one-pot hydrothermal route. The carbon-silica composite was employed as the precursor and cetyltrimethylammonium bromide (CTAB) as the morphology-controlled agent. SEM and TEM results indicated that the carbon shell and the silica core in the precursor were not closely linked but rattle-type structure. After removing the silica template, the obtained carbon product had uniform peapod-like morphology, interconnected pores and high specific surface areas (above 800.0 m(2)/g). We found that CTAB played an important role in the formation of the products with peapod-like morphology. The particle sizes of the hollow carbon nanospheres were readily adjusted by varying the dosage of tetraethoxysilane (TEOS) and the volume ratio of ethanol and water. Based on the experimental results, the formation mechanism of the hollow carbon nanomaterial was also discussed. By virtue of their unique nanostructure and porous properties, the peapod-like hollow carbon nanomaterial exhibited ultrahigh drug loading capacity above 98.4% for doxorubicin hydrochloride (DOX)., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Abstract: The assembly of two‐dimensional (2D) transition‐metal oxides and reduced graphene oxide (RGO) has shown great potential in photocatalysis, energy storage, and photoelectric devices. In the work, we present a 3‐aminopropyltriethoxysilane (APTES)‐induced interfacial assembly route for preparation of a new type of 2D TiO2@RGO hybrid nanostructure. Benefiting from the electrostatic interaction between APTES and RGO, followed by the hydrolysis of APTES, an ultrathin SiO2 layer is first well grown into the surface of RGO. Subsequently, ultrathin TiO2 nanosheets (about 4 nm in thickness) are uniformly decorated onto the surface of silica‐modified RGO. These robust TiO2 nanosheets interconnect each other and form a unique net‐like architecture. Significantly, the TiO2@RGO products show superior structural stability. Consequently, the TiO2@RGO product annealed at 750 °C demonstrates an excellent photocatalytic activity and a good cycling life for degradation of organic dyes such as methyl orange (MO), rhodamine B (RhB) and methyl blue (MB) owing to the unique construction and enhanced synergistic effect. [ABSTRACT FROM AUTHOR]

Here, a facile self-templating approach is presented for synthesis of hollow and yolk-shell mesoporous silica nanoparticles (HMSNs and YMSNs) through a selective etching of hybrid silica nanoparticles. The hybrid silica nanoparticles are from the co-condensation of tetraethylorthosilicate (TEOS) and N-[3-(trimethoxysilyl)propyl]ethylenediamine (TSD) by a simple one-step process. Two kinds of products including HMSNs and YMSNs can be easily prepared only by tuning the TSD amounts in the precursor. Significantly, the transformation of hollow structure does not use any sacrificial template and surface-protective agent. The etching mechanism and formation process are systematically investigated by SEM, TEM, TG, CHN elemental analysis and Si MAS NMR spectroscopy. The results reveal that the selective etching is mainly attributed to the discrepancy in density between the outer layer and inner area of hybrid silica, where its inner section is more readily dissolved while the outer shell is robust in hydrofluoric acid (HF) aqueous solution. Specifically, the new understanding is further extended to precisely prepare multi-shelled hollow/yolk-shell silica nanoparticles. [ABSTRACT FROM AUTHOR]

A simple hydrothermal route was designed to prepare 3D flower-like MoS2/graphene composites (FL-MoS2/graphene). Herein, two products, denoted C-FL-MoS2/graphene and N-FL-MoS2/graphene, were produced by facile glucose- and glucosamine-mediated methods, respectively. Both composites were found to show a well-defined morphology with a unique structure, in which the dispersed MoS2 nanoflowers are tightly anchored onto the graphene nanosheets. Moreover, the nanoflowers are constructed by a lot of wrinkled MoS2 thin nanosheets, which generates numerous open voids. In the process, glucose or glucosamine as the binder plays a similar role in regulating the growth of flower-like MoS2 on graphene. In terms of electrochemical performance, the FL-MoS2/graphene composite demonstrates superior lithium-storage capabilities, including a high reversible capacity, excellent cycle stability, and good rate capability, than N-MoS2/graphene (without the addition of any binder). Specifically, C-FL-MoS2/graphene shows a high reversible capacity of 980 mA h g−1 at a current of 100 mA g−1 even after 100 cycles, and a significantly improved high rate capability of 740 mA h g−1 is also retained at a current density of 1000 mA g−1. The remarkable performance of FL-MoS2/graphene was determined to result mainly from the unique architecture comprising 3D flower-like MoS2 particles and graphene nanosheets with superior conductivity. [ABSTRACT FROM AUTHOR]

In this work, In 2 O 3 microspheres with hierarchical nanostructures were successfully synthesized by solvothermal method in the presence of oleic acid and urea. The as-synthesized samples were characterized by X-ray powder diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM). The results indicate that the synthesized hierarchical In 2 O 3 consists of irregular nanorods. Moreover, the gas sensing properties of as-prepared In 2 O 3 hierarchical microspheres were investigated. It was found that the sensor based on such hierarchical nanostructures exhibited high response and good selectivity to NO 2 at 145 °C. [ABSTRACT FROM AUTHOR]

In the work, flower-like SnO 2 hierarchical nanostructures assembled with numerous nanosheets were successfully prepared through a facile template-free hydrothermal route using SnSO 4 as the tin source and water as the solvent. The process was simple, green, and effective. The obtained SnO 2 products had uniform flower-like morphology, hierarchical nanostructures, and high specific surface area of 136.0 m 2 /g. The investigation of the experimental parameters demonstrated that the tetrapropylammonium hydroxide (TPAOH) played a crucial role in determining the structure and properties of the final products, which was acted as both the alkali source and morphology director. Ag/SnO 2 nanostructures were also fabricated by a conventionally impregnation method, in which Ag nanoparticles with the size of 20–30 nm were uniformly grown into the surface of SnO 2 product. The gas sensing tests indicated that both SnO 2 and Ag/SnO 2 sensors exhibited better gas sensing properties to n-butanol at low working temperature of 160 °C compared with the sensor based on the commercial SnO 2 nanoparticles. As expected, the sensor based on the Ag/SnO 2 product showed obviously enhancement in gas sensing performance. The growth process and gas-sensing mechanism were investigated based on the experimental results. The present protocol may be extended to the synthesis of other metal oxides with different nanostructures for more potential applications. [ABSTRACT FROM AUTHOR]

Despite significant progress in the field of semiconductor photocatalysis has been made, it is still a great challenge to prepare low-cost photocatalysts with high activities. In our work, three dimensional (3D) flower-like ZnO hierarchical nanostructures assembled with numerous nanosheets were fabricated by a simple, template-free and one-step hydrothermal route. The products were characterized by XRD, UV–Vis, PL, SEM, TEM, HRTEM techniques. In the process, NH 4 F played a crucial role for the formation of ZnO hierarchical nanostructures, which was acted both as the alkali source and morphology director. Furthermore, the growth of ZnO involved a phase transformation from intermediate compound ZnF(OH) to ZnO. To further improve the photocatalytic activity, Ag-doped ZnO photocatalyst was also prepared. The photocatalytic results indicated that the Ag/ZnO exhibited higher photocatalytic activity than the pure ZnO. The great enhancement was mainly ascribed to their unique hierarchical nanostructures as well as the modification of Ag nanoparticles. Additionally, both ZnO and Ag/ZnO microspheres showed good recycling stabilities over several separation cycles in photodegradation. [ABSTRACT FROM AUTHOR]

A one-step hydrothermal process to convert Gd-doped titanium glycolate precursor nanospheres into TiO2:Gd mesoporous nanospheres by Ostwald ripening and to cause in situ Mo- and S-doping of TiO2 was investigated. Importantly, the photocatalytic ability of the Mo,S-doped TiO2:Gd mesoporous nanospheres was 3.8 times higher than that of the only S-doped samples and better than that of the MoS2 sub-microspheres under visible-light irradiation. Moreover, treatment of the samples under a low vacuum for 3 days (6.7 ± 0.7 Pa, 150 °C) reinforced the photocatalytic properties of the nanospheres and increased their efficiency threefold. [ABSTRACT FROM AUTHOR]

In this paper, rambutan-like SnO 2 hierarchical nanostructure assembled with a number of nanosheets has been successfully prepared through a facile hydrothermal route with the synergistic effect of block copolymer F127 (EO 106 -PO 70 -EO 106 ) and Na 3 C 6 H 5 O 7 . The structure and morphology were characterized by TEM, SEM, XRD, IR and BET techniques. The formation of SnO 2 architecture underwent the nucleation, oriented growth and a phase transformation process. Besides that, Ag/SnO 2 products with different amounts of Ag doping were also obtained. As gas-sensing materials, both SnO 2 and Ag/SnO 2 products demonstrated sensitive and selective response to several hazardous gases, especially for n-butanol at a low work temperature of 140 °C compared with the commercial SnO 2 . Significantly, the Ag/SnO 2 product with 5 wt% Ag doping exhibited the most excellent gas sensing proprieties of 44.3–100 ppm n-butanol at 140 °C with a fast response and recovery time of 8/5s. The improvement may on account of their unique nanostructures, large surface areas and the decoration of Ag nanoparticles. [ABSTRACT FROM AUTHOR]

The group IV semiconductors such as silicon (Si) and germanium (Ge) are unique materials with a wide range of technological applications. A versatile integrated device for the semiconductor industry is highly desirable for advanced applications. Notwithstanding the widespread application of Ge its use is not as extensive as that of Si, and nebulous domains in our understanding of its precise technical functions still remain. Previous nanostructures have either been one-dimensional nanomaterials such as nanowires, nanorods, nanobelts/nanoribbons, nanotubes, two-dimensional nanoscale thin films, or zero-dimensional nanoparticles, which all have integer dimensions. Herein, the non-integer dimensional Ge nanostructures, referred to as nanofractals, were successfully assembled by high-vacuum thermal evaporation techniques. We have found that the thermodynamically driven assemblies of Ge nanocrystals possess amazing nanostructures such as polycondensation-type Ge nanofractals with non-integer dimensions, thick branches and smooth edges, metastable gamma-Au0.6Ge0.4 nanocrystals, and a variety of interesting micro/nanometer-sized features. The results of computer simulations using a ripening mechanism of non-uniform grains agree very well with the patterns formed in experiments. [ABSTRACT FROM AUTHOR]