The assembly of hybrid nanomaterials has opened up a new direction for the construction of high-performance anodes for lithium-ion batteries (LIBs). In this work, we present a straightforward, eco-friendly, one-step hydrothermal protocol for the synthesis of a new type of Fe2O3-SnO2/graphene hybrid, in which zero-dimensional (0D) SnO2 nanoparticles with an average diameter of 8 nm and one-dimensional (1D) Fe2O3 nanorods with a length of ~150 nm are homogeneously attached onto two-dimensional (2D) reduced graphene oxide nanosheets, generating a unique point-line-plane (0D-1D-2D) architecture. The achieved Fe2O3-SnO2/graphene exhibits a well-defined morphology, a uniform size, and good monodispersity. As anode materials for LIBs, the hybrids exhibit a remarkable reversible capacity of 1,530 mA·g−1 at a current density of 100 mA·g−1 after 200 cycles, as well as a high rate capability of 615 mAh·g−1 at 2,000 mA·g−1. Detailed characterizations reveal that the superior lithium-storage capacity and good cycle stability of the hybrids arise from their peculiar hybrid nanostructure and conductive graphene matrix, as well as the synergistic interaction among the components.

•A novel kind of yolk-shell Ag@carbon nanostructures has been developed.•A facile selective-etching strategy has been proposed.•The void of the Ag@carbon products can be readily tuned.•The yolk-shell Ag@carbon nanoparticles show a superior catalytic activity.Yolk-shell nanostructures have attracted much attention because of their superior properties in various fields. In the present work, a facile self-etching route has been used to synthesize uniform and highly active yolk-shell Ag@carbon nanostructures by selective etching of Ag nanoparticles as the core under an acidic environment. Both the penetrable carbon shell and the empty inner space provide a homogenous environment for heterogeneous catalysis and effectively prevent aggregation of Ag nanoparticles. The well-built Ag@carbon yolk-shell nanoparticles exhibit remarkable catalytic activity and an excellent cycling stability for the reduction of 4-nitrophenol due to their uniform shape, penetrable carbon shell and stable nanostructure.Yolk-shell Ag@carbon nanostructures with superior catalytic performance have been successfully prepared by a facile selective-etching strategy.Download high-res image (129KB)Download full-size image

Nowadays, rattle-like or so-called yolk-shell nanostructures have set off a new wave of research in view of their prominent features including large surface area, tunable void and flexible functional core, etc. Herein, rattle-like mesoporous silica nanoparticles (RMSNs) with a pure silica core, a hollow cavity and a mesoporous shell have been successfully fabricated via a surfactant-assisted selective etching strategy. The synthetic approach involves the preparation of solid silica spheres with three-layer different structural silica containing the inner core of pure silica, middle layer of hybrid silica and outer shell of surfactant/SiO2 composite, followed by a hydrothermal treatment in hot water. The resulting products show a distinct rattle-like structure and spherical morphology. The average diameter, the shell thickness, and the solid core size of RMSNs are about 290, 35 and 90 nm, respectively. During the etching process, the surfactant with different length of alkyl chain (CnTAB, e.g. cetyltrimethylammonium bromide) in outer shell plays a decisive role for the formation of rattle-like structure. Benefiting from the residual amino groups in RMSNs, Au@RMSNs composites can be further constructed by in-situ generating Au nanoparticles into their hollow cavity, demonstrating an excellent catalytic performance for reduction of 4-nitrophenol. Additionally, RMSNs also show a strong ability for adsorption of rhodamine B.Download high-res image (57KB)Download full-size image

As an important semiconductor metal oxide, various methods have been developed for preparation of ZnO architectures owing to their excellent properties and extensive applications. In this paper, two kinds of 3D flower-like ZnO architectures assembled with numerous nanosheets were successfully synthesized by a simple hydrothermal route assisted by sodium dodecyl sulfate (SDS), origining from the different alkali environment created by urea and hexamine (HMT). SEM and TEM results revealed that the two products had hydrangea-like and rose-like nanostructures with uniform particle sizes, respectively. XRD results confirmed that the growth process of ZnO involved a phase transformation from intermediate compound basic zinc carbonate to ZnO. Base on the experimental results, the formation mechanisms of two kinds of flower-like ZnO undergoing nucleation, oriented growth and self-assembly processes were discussed. The photocatalytic results indicated that both samples exhibited high photocatalytic activities and good cycling stability for the degradation of rhodamine B (RhB), which was almost completely degraded within 25 min, in comparison to those milled samples (above 45 min). The excellent performances were mainly ascribed to their unique nanostructure, good stability, and uniform particle size.

In our work, rod-like SnO2 nanoparticles with tunable length have been successfully anchored onto graphene nanosheets through a simple and in situ hydrothermal strategy under acidic conditions. The SEM and TEM images demonstrate that the unique rod-like SnO2 nanoparticles with a diameter of 10–15 nm and length of 18–34 nm are uniformly anchored onto the surface of graphene nanosheets. Moreover, the particle sizes of rod-like SnO2 nanoparticles can be readily adjusted by simply varying the reaction temperature. Interestingly, with the increase of reaction temperature from 120 to 160 °C, the rod length of SnO2 nanoparticles significantly increased. More importantly, the SnO2@graphene products exhibit a very high specific surface area, which played a key role in maintaining the structural stability against the irreversible volume change during Li+ insertion/extraction. The nanocomposites show an extremely high lithium storage capability and an excellent cycling performance. The initial discharge capacities are 1284 mA h g−1 at current densities of 200 mA g−1. After 100 cycles, the discharge capacity still remains as high as 981 mA h g−1, indicating a superior retention capacity.

•A dual-templating route has been developed for synthesis of multi-shelled mesoporous silica nanoparticles (MMSNs).•The MMSNs display a spherical morphology, relatively uniform size distribution and good biocompatibility.•The Au-decorated MMSNs exhibit superior catalytic activity and good cycle stability for the reduction of 4-nitrophenol.•The MMSNs show high drug loading efficiency and the controlled pH-responsive release behavior for DOX.A facile vesicle-templating approach has been developed for synthesis of multi-shelled mesoporous silica nanoparticles (MMSNs) through a self-assembly of cetyltrimethylammonium bromide (CTAB) and sodium dodecyl benzene sulfonate (SDBS). The obtained MMSNs displayed a spherical morphology, relatively uniform size distribution with an average diameter of 185 nm and a good biocompatibility. Controlled experiments demonstrated that the morphology and structure of MMSNs were mainly determined by the mass ratio of CTAB/SDBS in the reagents. A possible growth mechanism of MMSNs was proposed based on TEM, SEM, and N2 sorption analysis, etc. Moreover, the Au-decorated MMSNs (Au@MMSNs) were constructed as the catalyst, which exhibited superior catalytic activity and good cycle stability for the reduction of 4-nitrophenol (4-NP). Additionally, the MMSNs also showed high drug loading efficiency and the controlled pH-responsive release behavior for doxorubicin hydrochloride (DOX). More importantly, the anticancer effect of DOX@MMSNs towards A549 cell further confirmed MMSNs could be employed as an ideal drug carrier. As a consequence, the MMSNs prepared are potential excellent candidates for various applications including nanoreactors, drug delivery, and cancer therapy.

In this study, a series of mesoporous silica nanoparticles (MSNs) with well-defined morphologies and diverse pore structures have been successfully fabricated under alkaline conditions. In this case, cetyltrimethylammonium bromide (CTAB) was employed as the structure-directing agent, ethylacetate (EA) as the co-template, ethanol and water as co-solvents. By simply tuning the volume of ethanol in the reaction precursor, the trilobite-like nanoparticles, unique nanospheres with parallel and radical pores, and worm-like pore structure nanoparticles were obtained. The silica nanostructures were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), N2 adsorption–desorption measurement, etc. During the synthesis process, the lamellar micelles and microemulsion droplets formed in an oil–water (O/W) mixture played a key role for the formation of diverse MSNs. Additionally, the as-prepared MSNs showed good biocompatibility and high drug storage capability for ibuprofen (IBU) loading. More importantly, when used as a nanoreactor for constructing the novel functionalized Au@MSNs nanocomposites, they exhibited superior catalytic activities for the reduction of 4-nitrophenol (4-NP). The present findings could provide more possibilities for the controllable fabrication of silica nanomaterials and their potential applications.

•Rambutan-like SnO2 architecture is assembled with numerous nanosheets.•Block copolymer F127 plays a key role.•The formation of SnO2 architecture undergoes a phase transformation process.•Both SnO2 and Ag/SnO2 products demonstrate superior gas-sensing performances.In this paper, rambutan-like SnO2 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 (EO106-PO70-EO106) and Na3C6H5O7. The structure and morphology were characterized by TEM, SEM, XRD, IR and BET techniques. The formation of SnO2 architecture underwent the nucleation, oriented growth and a phase transformation process. Besides that, Ag/SnO2 products with different amounts of Ag doping were also obtained. As gas-sensing materials, both SnO2 and Ag/SnO2 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 SnO2. Significantly, the Ag/SnO2 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.

In recent years, a lot of metal oxides with high theoretical capacity have widely investigated as the high-performance anode materials for lithium-ion batteries (LIBs). In this work, a simple, facile and effective one-pot hydrothermal strategy toward ternary SnO2–TiO2@graphene composite has been developed by using SnCl2 and TiOSO4 as the starting materials. The obtained composite demonstrates a unique structure and high surface areas, in which both SnO2 and TiO2 nanoparticles are well grown on the surface of graphene. More interestingly, the SnO2 and TiO2 nanoparticles are intergrowth together, totally different with the traditional ternary hybrids. When used as anode material for LIBs, the introduction of TiO2 plays a crucial role in maintaining the structural stability of the electrode during Li+ insertion/extraction, which can effectively prevent the aggregation of SnO2 nanoparticles. The electrochemical tests indicate that as-prepared SnO2–TiO2@graphene composite exhibits a high capacity of 1276 mA h g−1 after 200 cycles at the current density of 200 mA g−1. Furthermore, the composite also maintains the specific capacity of 611 mA h g−1 at an ultrahigh current density of 2000 mA g−1, which is superior to those of the reported SnO2 and SnO2/graphene hybrids. Accordingly, the remarkable electrochemical performance of ternary SnO2–TiO2@graphene composites is mainly attributed to their unique nanostructure, high surface areas, and the synergistic effect not only between graphene and metal oxides but also between the intergrown SnO2 and TiO2 nanoparticles.

In this work, a novel type of hollow mesoporous silica nanoparticle (HMSN) with a rough surface has been successfully prepared via a facile soft–hard template route by using a carbon nanosphere as a hard template and cetyltrimethylammonium bromide (CTAB) as a soft template, respectively. This method involves the preparation of a carbon nanosphere, sequential coating of double SiO2 layers, and the removal of the inner carbon core and CTAB to produce HMSNs. The obtained HMSNs possess spherical morphology, a mesoporous shell, and crumpled surfaces. The controlled experiments prove that the addition of 3-ammonia propyl triethoxy silane (APTES) is very crucial for the formation of desired HMSNs. The cell tests indicate that HMSNs show a good biocompatibility. As a result, the potential applications of HMSNs are further explored for drug delivery and protein adsorption, using doxorubicin hydrochloride (DOX) and Cytochrome c (Cyt c) as the model drug and protein, respectively. The HMSNs exhibit high drug loading and protein adsorption capacity, as well as the controlled pH-responsive release behavior for DOX. Therefore, the HMSNs prepared are ideal candidates for various applications such as nanoreactors, drug delivery and protein adsorption.

In our work, two kinds of hollow carbon nanospheres with controlled morphologies have been successfully prepared from low-cost and nontoxic glucose as the sole carbon precursor under neutral aqueous medium via a simple hydrothermal route. During the process, sodium dodecylbenzene sulfonate (SDBS) and triblock copolymer P123 ((EO)20(PO)70(EO)20) was skillfully selected as the structure-directing agent, respectively. SEM, TEM and AFM results revealed that the two products showed bowl-like and deflated-balloon-like morphology with uniform particle sizes, respectively. Based on the experimental observations, a possible formation mechanism was also discussed, in which the growth of the carbon nanospheres involved an interface-medicated assembly process. The present method was easy, green and mild. Apart from the unique nanostructure, the obtained bowl-like hollow carbon nanospheres exhibited excellent biocompatibility. In particular, it should be mentioned that the open window formed by the bowl-like morphology can facilitate ion transport, thus improving their performances.

•A facile one-pot co-template synthesis route has been developed for the preparation of the peapod-like hollow carbon nanomaterials.•The hollow carbon materials possess high specific surface area, porous shell, uniform morphology, and controlled particle size.•The formation mechanism is discussed based on the experimental results.•The peapod-like hollow carbon nanomaterial exhibited ultrahigh drug loading capacity for doxorubicin hydrochloride (DOX).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 m2/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).

In the paper, an environmentally friendly and template-free route based on a simple hydrothermal process has been developed for preparing rattle-type TiO2 hollow microspheres by using titanium(IV) sulfate (Ti(SO4)2) as the titanium source and glycerol/water as the cosolvent. The SEM and TEM images showed that the obtained TiO2 products were rattle-type hollow nanostructures with a diameter of ca. 1.1 μm. More importantly, the products have a good thermal stability and high crystallinity, which is favorable for their practical applications. According to the experimental results, a possible formation mechanism involving the Ostwald ripening process was proposed combined with various techniques such as SEM, TEM, BET, IR, and UV-vis. The photocatalytic results indicated that the TiO2 microspheres obtained from 750 °C thermal treatment exhibited higher photocatalytic activity for the photodegradation of methyl orange (MO) than those of other calcination temperatures and commercial Degussa P25. To further improve the photocatalytic activity, Ag-doped TiO2 photocatalyst was also prepared by the impregnation method. The results indicated that the photocatalytic activity of the Ag/TiO2 catalysts was greatly enhanced compared with the pure TiO2 catalysts. The possible photodegradation mechanism was also discussed.

In this paper, three-dimensional flower-like ZnO hierarchical nanostructures were fabricated from the thermal-decomposition of 3D zinc hydroxide carbonate precursor, which was synthesized by a urea hydrothermal method with block copolymer F127 (EO106-PO70-EO106) as the morphology director. XRD, IR, UV-vis, SEM, TEM, TG and N2 adsorption–desorption isotherms have been employed to characterize the products. The influences of synthesis parameters such as reaction time, the type of zinc sources, and species concentration on the morphologies of the products were systematically studied. It was found that the reaction time played a key role in determining the final morphology of porous ZnO. On the basis of experimental results, a possible formation mechanism of the 3D flower-like ZnO hierarchical nanostructures was discussed. More importantly, the gas sensing tests indicated that the sensor made from porous ZnO hierarchical nanostructures exhibited better gas sensing properties to n-butanol compared with the sensor based on the commercial ZnO nanoparticles. The enhancement in gas sensing properties was attributed to their unique 3D hierarchical nanostructures, high surface areas, and greater number of surface active sites.

Mesoporous silicon carbides (SiC) with high surface areas (above 300 m2/g) have been prepared successfully at a relative low temperature of 650 °C via magnesiothermic reduction of mesoporous silica/carbon (SiO2/C) composites. The physicochemical properties and the structure of the products were characterized by various techniques such as XRD, FT-IR, SEM, TEM and N2 adsorption–desorption isotherm. The experimental results indicate that the obtained SiC materials by this new method have similar structure to corresponding silica matrix templates. It was found that the magnesium (Mg) plays an important role in determining the structure and properties of the final products, which is used as a dual role agent both reducer and catalyst. The formation mechanism of mesoporous SiC has been also discussed.

Mesoporous SnO2 was synthesized using cetyltrimethyl ammonium bromide (CTAB) as supermolecule-template by hydrothermal method followed by calcining under different temperature in air. X-ray diffraction analysis (XRD) and transmission electron microscopy (TEM) techniques were used to characterize the structure of mesoporous SnO2. The results indicated that the gas sensors prepared by using mesoporous SnO2 after calcination at 400 °C showed quick response and recovery to ethanol at 200 °C. It was also found that the mesostructure SnO2 with small particle size had higher sensitivity and selectivity to C2H5OH than the SnO2 nanoparticles the particle size of which is 20 nm synthesized by sol-gel method.

Core-shell LiFePO4@C composites were synthesized successfully from FePO4/C precursor using the polyvinyl alcohol (PVA) as the reducing agent, followed by a chemical vapor deposition (CVD) assisted solid-state reaction in the presence of Li2CO3. Some physical and chemical properties of the products were characterized by X-ray powder diffraction (XRD), Raman, SEM, TEM techniques. The effect of morphology and electrochemical properties of the composites were thoroughly investigated. XRD patterns showed that LiFePO4 has an order olivine structure with space group of Pnma. TEM micrographs exhibited that the LiFePO4 particles encapsulated with 3-nm thick carbon shells. The powders were homogeneous with grain size of about 0.8 μm. Compared with those synthesized by traditional organic carbon source mixed method, LiFePO4@C composite synthesized by CVD method exhibited better discharge capacity at initial 155.4 and 135.8 mAh g−1 at 0.1C and 1C rate, respectively. It is revealed that the carbon layer coated on the surface of LiFePO4 and the amorphous carbon wrapping and connecting the particles enhanced the electronic conductivity and rate performances of the cathode materials.

In this work, a novel type of hollow mesoporous silica nanoparticle (HMSN) with a rough surface has been successfully prepared via a facile soft–hard template route by using a carbon nanosphere as a hard template and cetyltrimethylammonium bromide (CTAB) as a soft template, respectively. This method involves the preparation of a carbon nanosphere, sequential coating of double SiO2 layers, and the removal of the inner carbon core and CTAB to produce HMSNs. The obtained HMSNs possess spherical morphology, a mesoporous shell, and crumpled surfaces. The controlled experiments prove that the addition of 3-ammonia propyl triethoxy silane (APTES) is very crucial for the formation of desired HMSNs. The cell tests indicate that HMSNs show a good biocompatibility. As a result, the potential applications of HMSNs are further explored for drug delivery and protein adsorption, using doxorubicin hydrochloride (DOX) and Cytochrome c (Cyt c) as the model drug and protein, respectively. The HMSNs exhibit high drug loading and protein adsorption capacity, as well as the controlled pH-responsive release behavior for DOX. Therefore, the HMSNs prepared are ideal candidates for various applications such as nanoreactors, drug delivery and protein adsorption.