1D necklace-like nanostructures have exhibited different potential applications due to their unique geometry and property. However, their macroscopic and controllable synthesis has been a challenge. Herein, a facile and scalable template-directed hydrothermal process is reported to synthesize a series of necklace-like phenol-formaldehyde resin (PFR) wrapped nanocables. The 1D templates involved in the synthesis can be various, such as tellurium nanowires (TeNWs), silver nanowires, and carbon nanotubes. After removal of the TeNWs template, pure PFR necklace-like nanofibers with different morphologies can be prepared. Owning to their multiscale roughness and formed 3D network structures, such necklace-like PFR nanofibers can be further used as building blocks for constructing robust superhydrophobic coatings with excellent mechanical properties on various substrates.

Rechargeable Li batteries based on group VIA element cathodes, such as tellurium, are emerging due to their capability to provide equivalent theoretical volumetric capacity density to O and S, as well as an improved activity to react with Li. Herein, bifunctional and elastic carbon nanotube (CNT) aerogel is fabricated to combine with Te nanowires, yielding two types of binder/collector-free Te cathodes to assemble Li-Te batteries. The CNTs with high electronic conductivity and hollow porous structure enable stable electric contact and fast transportation of Li⁺, while trapping Te and Li₂Te in its network, triggering fast and stable Li-Te electrochemistry. Both cathodes are also provided with fine compressibility, helping to buffer their volume changes during lithiation/delithiation and improving electrode integrity. Both cathodes deliver high specific capacity, fine cycling stability, and favorable high-rate capability, proving their competence in building high-energy rechargeable Li-ion batteries.

Charged inorganic nanowires (e.g., tellurium nanowires, TeNWs), analogous to supramolecular templates, have been used to direct the mineralization of uniform amorphous calcium carbonate (ACC) shells on their surfaces. The role of surface charges of TeNWs, mixed solvent ratio, and the diameter of the TeNWs is discussed, and the formation mechanism of ACC-coated tellurium nanowires (ACC@TeNWs) is elucidated. This charged-nanowire-directed mineralization process represents a new approach that could be extended for the synthesis of other amorphous inorganic nanostructures in the future.

Exploring low-cost and high-performance nonprecious metal catalysts (NPMCs) for oxygen reduction reaction (ORR) in fuel cells and metal–air batteries is crucial for the commercialization of these energy conversion and storage devices. Here we report a novel NPMC consisting of Fe₃C nanoparticles encapsulated in mesoporous Fe-N-doped carbon nanofibers, which is synthesized by a cost-effective method using carbonaceous nanofibers, pyrrole, and FeCl₃ as precursors. The electrocatalyst exhibits outstanding ORR activity (onset potential of −0.02 V and half-wave potential of −0.140 V) closely comparable to the state-of-the-art Pt/C catalyst in alkaline media, and good ORR activity in acidic media, which is among the highest reported activities of NPMCs.

Exploring low-cost and high-performance nonprecious metal catalysts (NPMCs) for oxygen reduction reaction (ORR) in fuel cells and metal–air batteries is crucial for the commercialization of these energy conversion and storage devices. Here we report a novel NPMC consisting of Fe₃C nanoparticles encapsulated in mesoporous Fe-N-doped carbon nanofibers, which is synthesized by a cost-effective method using carbonaceous nanofibers, pyrrole, and FeCl₃ as precursors. The electrocatalyst exhibits outstanding ORR activity (onset potential of −0.02 V and half-wave potential of −0.140 V) closely comparable to the state-of-the-art Pt/C catalyst in alkaline media, and good ORR activity in acidic media, which is among the highest reported activities of NPMCs.

Biomedical applications of nontoxic amorphous calcium carbonate (ACC) nanoparticles have mainly been restricted because of their aqueous instability. To improve their stability in physiological environments while retaining their pH-responsiveness, a novel nanoreactor of ACC–doxorubicin (DOX)@silica was developed for drug delivery for use in cancer therapy. As a result of its rationally engineered structure, this nanoreactor maintains a low drug leakage in physiological and lysosomal/endosomal environments, and responds specifically to pH 6.5 to release the drug. This unique ACC–DOX@silica nanoreactor releases DOX precisely in the weakly acidic microenvironment of cancer cells and results in efficient cell death, thus showing its great potential as a desirable chemotherapeutic nanosystem for cancer therapy.

Template-directed synthesis of nanostructures has been emerging as one of the most important synthetic methodologies. A pristine nanotemplate is usually chemically transformed into other compounds and sacrificed after templating or only acts as an inert physical template to support the new components. If a nanotemplate is costly or toxic as waste, to recycle such a nanotemplate becomes highly desirable. Recently, ultrathin tellurium nanowires (TeNWs) have been demonstrated as versatile chemical or physical templates for the synthesis of a diverse family of uniform 1D nanostructures. However, ultrathin TeNWs as template are usually costly and are discarded as toxic waste in ionic species after chemical reactions or erosion. To solve the above problem, we conceptually demonstrate that such a nanotemplate can be economically recycled from waste solutions and repeatedly used as template.

Resorcinol–formaldehyde (RF) and graphene oxide (GO) aerogels have found a variety of applications owing to their excellent properties and remarkable flexibility. However, the macroscopic and controllable synthesis of their composite gels is still a great challenge. By using GO sheets as template skeletons and metal ions (Co²⁺, Ni²⁺, or Ca²⁺) as catalysts and linkers, the first low-temperature scalable strategy for the synthesis of a new kind of RF–GO composite gel with tunable densities and mechanical properties was developed. The aerogels can tolerate a strain as high as 80 % and quickly recover their original morphology after the compression has been released. Owing to their high compressibility, the gels might find applications in various areas, for example, as adsorbents for the removal of dye pollutants and in oil-spill cleanup.

Biomedical applications of nontoxic amorphous calcium carbonate (ACC) nanoparticles have mainly been restricted because of their aqueous instability. To improve their stability in physiological environments while retaining their pH-responsiveness, a novel nanoreactor of ACC–doxorubicin (DOX)@silica was developed for drug delivery for use in cancer therapy. As a result of its rationally engineered structure, this nanoreactor maintains a low drug leakage in physiological and lysosomal/endosomal environments, and responds specifically to pH 6.5 to release the drug. This unique ACC–DOX@silica nanoreactor releases DOX precisely in the weakly acidic microenvironment of cancer cells and results in efficient cell death, thus showing its great potential as a desirable chemotherapeutic nanosystem for cancer therapy.

Resorcinol–formaldehyde (RF) and graphene oxide (GO) aerogels have found a variety of applications owing to their excellent properties and remarkable flexibility. However, the macroscopic and controllable synthesis of their composite gels is still a great challenge. By using GO sheets as template skeletons and metal ions (Co²⁺, Ni²⁺, or Ca²⁺) as catalysts and linkers, the first low-temperature scalable strategy for the synthesis of a new kind of RF–GO composite gel with tunable densities and mechanical properties was developed. The aerogels can tolerate a strain as high as 80 % and quickly recover their original morphology after the compression has been released. Owing to their high compressibility, the gels might find applications in various areas, for example, as adsorbents for the removal of dye pollutants and in oil-spill cleanup.

Rigid biological systems are increasingly becoming a source of inspiration for the fabrication of next generation advanced functional materials due to their diverse hierarchical structures and remarkable engineering properties. Among these rigid biomaterials, nacre, as the main constituent of the armor system of seashells, exhibiting a well-defined ‘brick-and-mortar’ architecture, excellent mechanical properties, and interesting iridescence, has become one of the most attractive models for novel artificial materials design. In this review, recent advances in nacre-inspired artificial carbonate nanocrystals and layered structural nanocomposites are presented. To clearly illustrate the inspiration of nacre, the basic principles relating to plate-like aragonite single-crystal growth and the contribution of hierarchical structure to outstanding properties in nacre are discussed. The inspiration of nacre for the synthesis of carbonate nanocrystals and the fabrication of layered structural nanocomposites is also discussed. Furthermore, the broad applications of these nacre inspired materials are emphasized. Finally, a brief summary of present nacre-inspired materials and challenges for the next generation of nacre-inspired materials is given.

Recently, heteroatom-doped three-dimensional (3D) nanostructured carbon materials have attracted immense interest because of their great potential in various applications. Hence, it is highly desirable to exploit a simple, renewable, scalable, multifunctional, and general strategy to engineer 3D heteroatom-doped carbon nanomaterials. Herein, a simple, eco-friendly, general, and effective way to fabricate 3D heteroatom-doped carbon nanofiber networks on a large scale is reported. Using this method, 3D P-doped, N,P-co-doped, and B,P-co-doped carbon nanofiber networks are successfully fabricated by the pyrolysis of bacterial cellulose immersed in H₃PO₄, NH₄H₂PO₄, and H₃BO₃/H₃PO₄ aqueous solution, respectively. Moreover, the as-prepared N,P-co-doped carbon nanofibers exhibit good supercapacitive performance.

Developing a reliable technique to organize nanoscale building blocks into ordered one-dimensional assemblies is of particular interest in a range of practical applications. Here, for the first time, it is reported that platinum (Pt) nanoparticle chain networks can be assembled spontaneously in solution on a large scale. The in-situ induced magnetic dipoles are believed to be the driving force for producing such elegant assembled nanochains. The alterant electronic structure of Pt modified by a very thin layer of polyvinylpyrrolidone (PVP) molecules leads to the ferromagnetism of Pt (a traditional paramagnetic metal), which has been verified by a series of analysis techniques and theoretical modeling. The temperature- and time-dependent nucleation, growth, and organization processes of Pt chain networks are carefully investigated. These findings not only present the uncommon ferromagnetism of Pt, but also raise a possibility for expanding this strategy towards other assemblies of nonmagnetic nanoscale building blocks.

As macroscopic three dimensional (3D) architectures show increasing significance, much effort has been devoted to the hierarchical organization of 1D nanomaterials into serviceable macroscopic 3D assemblies. How to assemble 1D nanoscale building blocks into 3D hierarchical architectures is still a challenge. Herein we report a general strategy based on the use of ice as a template for assembling 1D nanostructures with high efficiency and good controllability. Free-standing macroscopic 3D Ag nanowire (AgNW) assemblies with hierarchical binary-network architectures are then fabricated from a 1D AgNW suspension for the first time. The microstructure of this 3D AgNW network endows it with electrical conductivity and allows it to be made into stretchable and foldable conductors with high electromechanical stability. These properties should make this kind of macroscopic 3D AgNW architecture and it composites suitable for electronic applications.

Traditional lithium-ion batteries that are based on layered Li intercalation electrode materials are limited by the intrinsically low theoretical capacities of both electrodes and cannot meet the increasing demand for energy. A facile route for the synthesis of a new type of composite nanofibers, namely carbon nanofibers decorated with molybdenum disulfide sheets (CNFs@MoS₂), is now reported. A synergistic effect was observed for the two-component anode, triggering new electrochemical processes for lithium storage, with a persistent oxidation from Mo (or MoS₂) to MoS₃ in the repeated charge processes, leading to an ascending capacity upon cycling. The composite exhibits unprecedented electrochemical behavior with high specific capacity, good cycling stability, and superior high-rate capability, suggesting its potential application in high-energy lithium-ion batteries.

Manipulating nanowire assembly could help the design of hierarchical structures with unique functionalities. Herein, we first report a facile solution-based process under ambient conditions for co-assembling two kinds of nanowires which have suitable composition and functionalities, such as Ag and Te nanowires, for the fabrication of flexible transparent electrodes. Then Te nanowires can be etched away easily, leaving Ag nanowire networks with controllable pitch. By manipulating the assembly of Ag and Te nanowires, we can precisely tailor and balance the optical transmittance and the conductivity of the resulting flexible transparent electrodes. The network of Ag nanowires which have tunable pitch forms a flexible transparent conducting electrode with an averaged transmission of up to 97.3 % and sheet resistances as low as 2.7 Ω/sq under optimized conditions. The work provides a new way for tailoring the properties of nanowire-based devices.

Traditional lithium-ion batteries that are based on layered Li intercalation electrode materials are limited by the intrinsically low theoretical capacities of both electrodes and cannot meet the increasing demand for energy. A facile route for the synthesis of a new type of composite nanofibers, namely carbon nanofibers decorated with molybdenum disulfide sheets (CNFs@MoS₂), is now reported. A synergistic effect was observed for the two-component anode, triggering new electrochemical processes for lithium storage, with a persistent oxidation from Mo (or MoS₂) to MoS₃ in the repeated charge processes, leading to an ascending capacity upon cycling. The composite exhibits unprecedented electrochemical behavior with high specific capacity, good cycling stability, and superior high-rate capability, suggesting its potential application in high-energy lithium-ion batteries.

Recently, porous hydrophobic/oleophilic materials (PHOMs) have been shown to be the most promising candidates for cleaning up oil spills; however, due to their limited absorption capacity, a large quantity of PHOMs would be consumed in oil spill remediation, causing serious economic problems. In addition, the complicated and time-consuming process of oil recovery from these sorbents is also an obstacle to their practical application. To solve the above problems, we apply external pumping on PHOMs to realize the continuous collection of oil spills in situ from the water surface with high speed and efficiency. Based on this novel design, oil/water separation and oil collection can be simultaneously achieved in the remediation of oil spills, and the oil sorption capacity is no longer limited to the volume and weight of the sorption material. This novel external pumping technique may bring PHOMs a step closer to practical application in oil spill remediation.

Manipulating nanowire assembly could help the design of hierarchical structures with unique functionalities. Herein, we first report a facile solution-based process under ambient conditions for co-assembling two kinds of nanowires which have suitable composition and functionalities, such as Ag and Te nanowires, for the fabrication of flexible transparent electrodes. Then Te nanowires can be etched away easily, leaving Ag nanowire networks with controllable pitch. By manipulating the assembly of Ag and Te nanowires, we can precisely tailor and balance the optical transmittance and the conductivity of the resulting flexible transparent electrodes. The network of Ag nanowires which have tunable pitch forms a flexible transparent conducting electrode with an averaged transmission of up to 97.3 % and sheet resistances as low as 2.7 Ω/sq under optimized conditions. The work provides a new way for tailoring the properties of nanowire-based devices.

As macroscopic three dimensional (3D) architectures show increasing significance, much effort has been devoted to the hierarchical organization of 1D nanomaterials into serviceable macroscopic 3D assemblies. How to assemble 1D nanoscale building blocks into 3D hierarchical architectures is still a challenge. Herein we report a general strategy based on the use of ice as a template for assembling 1D nanostructures with high efficiency and good controllability. Free-standing macroscopic 3D Ag nanowire (AgNW) assemblies with hierarchical binary-network architectures are then fabricated from a 1D AgNW suspension for the first time. The microstructure of this 3D AgNW network endows it with electrical conductivity and allows it to be made into stretchable and foldable conductors with high electromechanical stability. These properties should make this kind of macroscopic 3D AgNW architecture and it composites suitable for electronic applications.

Recently, porous hydrophobic/oleophilic materials (PHOMs) have been shown to be the most promising candidates for cleaning up oil spills; however, due to their limited absorption capacity, a large quantity of PHOMs would be consumed in oil spill remediation, causing serious economic problems. In addition, the complicated and time-consuming process of oil recovery from these sorbents is also an obstacle to their practical application. To solve the above problems, we apply external pumping on PHOMs to realize the continuous collection of oil spills in situ from the water surface with high speed and efficiency. Based on this novel design, oil/water separation and oil collection can be simultaneously achieved in the remediation of oil spills, and the oil sorption capacity is no longer limited to the volume and weight of the sorption material. This novel external pumping technique may bring PHOMs a step closer to practical application in oil spill remediation.

Induction of autophagy is a common response of cells upon exposure to nanomaterials and represents both a safety concern and an application niche for engineered nanomaterials. Herein, it is reported that the magnetic property and the autophagy-inducing activity for Ni–Co alloy nanocrystal (NC) assemblies can be differentially “tuned” through altering the material composition. A series of Ni–Co alloy NC assemblies, composed of nanoparticles (NPs) with a size of about 30 nm, can be quickly synthesized under microwave irradiation in aqueous solution. A controllable self-assembling effect is observed due to the strong magnetic moment of NPs and external magnetic field. Interestingly, the saturation magnetization (Ms) shows a ‘roller coaster’ effect with varying component molar ratio, while the autophagy-inducing activity and toxicity of these alloy NCs presents an elevated tendency with the increase of nickel component. The autophagic response partly contributes to the observed cellular toxicity of the NC assemblies, as inhibition of autophagy partially but significantly reduces toxicity. Therefore, through tuning the composition of the alloy, optimal Ni–Co NCs satisfying the needs of different applications such as diagnostic imaging (maximum magnetization and low autophagic response) or magnetically-directed cancer cell killing (maximum autophagic response and sufficient magnetization) may be designed and developed.

β-AgVO₃, as a stable phase and a typical silver vanadium oxide, has performed special ionic and electrical properties. The construction of nanoelectronic devices based on ultralong β-AgVO₃ nanoribbons (NRs) is reported, including nano-field-effect transistor (nano-FET) and nano-Schottky barrier diode (nano-SBD). Owing to the specific channel structure and ion conductivity, the nano-FET exhibits typical p-type semiconductor characteristics and the nano-SBD with Al contacts performs a prominent rectifying behavior with an on/off ratio of up to 10³. Besides, tunable electrical transport properties can be achieved by tailoring the material properties, and it is demonstrated that the bridging NR numbers and diameters have a positive effect on electrical transport properties, while a complex variation trend is observed in the case of surface modification by photo-irradiation. Electron spin resonance (ESR) spectrum further illuminates that the induced vacancies play an important role on the electrical transport properties of β-AgVO₃ nanoribbons. Easy access to the ultralong β-AgVO₃ NRs makes them a promising candidate for potential applications in nanoelectronic devices.

Herein, a kind of novel monocomponent hydrophilic and paramagnetic manganese(II) oxide nanocrystal is prepared in polar solution by a one-pot microwave-assisted synthesis. This kind of nanocrystal can be taken up efficiently to serve as an excellent T₁ magnetic resonance imaging (MRI) contrast agent with an enhanced r₁ value of 0.81 mM⁻¹ s⁻¹. The key to the success of this method is that no additional capping agents are required for coating onto the surface via ligand exchange, facilitating research of their intrinsic biological activities. Furthermore, multiple lines of convincing evidence are presented to prove that MnO nanocrystals (NCs) elicit p53-activation-independent and authentic functional autophagy via inducing autophagosome formation. Notably, there are very few reports so far of the autophagy phenomenon induced by magnetic nanocrystals. Moreover, these results offer an indication for cancer therapy that MnO NCs combined with doxorubicin at a nontoxic concentration can have a definite synergistic effect, which is mediated through the genuine autophagy induction, on killing cancer cells in vitro and in vivo.

Iron sulfide compounds are emerging as an important family of functional materials owing to their important properties and their applications in different technical fields. Well-defined Fe₇S₈ nanowires templated by thermal decomposition of [Fe₁₆S₂₀]/diethylenetriamine hybrid nanowires under an argon atmosphere are reported. As-prepared Fe₇S₈ nanowires show typical Michaelis–Menten kinetics and good affinity to both H₂O₂ and 3,3′,5,5′-tetramethylbenzidine. At pH 7.0, the constructed UV/Vis sensor showed a linear range for the detection of H₂O₂ from 0.5 to 150 μM with a correlation coefficient of 0.9998. The H₂O₂ sensor based on the Fe₇S₈ nanowires shows a highly sensitive response and has better stability than horseradish peroxidase when exposed to solutions with different pH values and temperatures. These excellent properties make the as-prepared Fe₇S₈ nanowires powerful tools for potential applications as an “artificial peroxidase” in biosensors and biotechnology.

A photothermally sensitive poly(N-isopropylacrylamide)/graphene oxide (PNIPAM/GO) nanocomposite hydrogel can be synthesized by in situ γ-irradiation-assisted polymerization of an aqueous solution of N-isopropylacrylamide monomer in the presence of graphene oxide (GO). The colors and phase-transition temperatures of the PNIPAM/GO hydrogels change with different GO doping levels. Due to the high optical absorbance of the GO, the nanocomposite hydrogel shows excellent photothermal properties, where its phase transitions can be controlled remotely by near-infrared (NIR) laser irradiation, and it is completely reversible via laser exposure or non-exposure. With a higher GO loading, the NIR-induced temperature of the nanocomposite hydrogel increases more quickly than with a lower doping level and the temperature can be tuned effectively by the irradiation time. The nanocomposite hydrogel with its excellent photothermal properties will have great applications in the biomedical field, especially as microfluidic devices; this has been demonstrated in our experiments by way of remote microvalves to control fluidic flow. Such an “easy” and “clean” synthetic procedure initiated by γ-irradiation can be extended for the efficient synthesis of other nanocomposite materials.

Multifunctional Ag@Au@ phenol formaldehyde resin (PFR) particles loaded with folic acids (FA) have been designed for killing tumor cells through photothermy conversion under the irradiation of near-infrared (NIR) light. Possessing the virtue of good fluorescence, low toxicity, and good targeting, the nanocomposite consists of an Ag core, an Au layer, a PFR shell, and folic acids on the PFR shell. The Ag@PFR core–shell structure can be prepared with a simple hydrothermal method after preheating. We then filled the PFR shell with a layer of Au by heating and modified the shell with polyelectrolyte to change its surface charge state. To capture tumor cells actively, FA molecules were attached onto the surface of the Ag@Au@PFR particles in the presence of 1-ethyl-3-(3-dimethly aminopropyl) carbodiimide (EDAC) and N-hydroxysuccinimide (NHS). Owing to the excellent property of Au NPs and Ag NPs as photothermal conversion agents, the Ag@Au@ PFR@FA particles can be utilized to kill tumor cells when exposed to NIR light.

Carbide-based electrocatalysts are superior to traditional carbon-based electrocatalysts, such as the commercial Pt/C electrocatalysts, in terms of their mass activity and stability. Herein, we report a general approach for the preparation of a nanocomposite electrocatalyst of platinum and vanadium carbide nanoparticles that are loaded onto graphitized carbon. The nanocomposite, which was prepared in a localized and controlled fashion by using an ion-exchange process, was an effective electrocatalyst for the oxygen-reduction reaction (ORR). Both the stability and the durability of the Pt-VC/GC nanocomposite catalyst could be enhanced compared with the state-of-the-art Pt/C. This approach can be extended to the synthesis of other metal-carbide-based nanocatalysts. Moreover, this straightforward synthesis of high-performance composite nanocatalysts can be scaled up to meet the requirements for mass production.

A family of monodisperse YF₃, YF₃:Ce³⁺ and YF₃:Ce³⁺/Ln³⁺ (Ln=Tb, Eu) mesocrystals with a morphology of a hollow spindle can be synthesized by a solvothermal process using yttrium nitrate and NH₄F as precursors. The effects of reaction time, fluorine source, solvents, and reaction temperature on the synthesis of these mesocrystals have been studied in detail. The results demonstrate that the formation of a hollow spindle-like YF₃ can be ascribed to a nonclassical crystallization process by means of a particle-based reaction route in ethanol. It has been shown that the fluorine sources selected have a remarkable effect on the morphologies and crystalline phases of the final products. Moreover, the luminescent properties of Ln³⁺-doped and Ce³⁺/Ln³⁺-co-doped spindle-like YF₃ mesocrystals were also investigated. It turns out that Ce³⁺ is an efficient sensitizer for Ln³⁺ in the spindle-like YF₃ mesocrystals. Remarkable fluorescence enhancement was observed in Ce³⁺/Ln³⁺-co-doped YF₃ mesocrystals. The mechanism of the energy transfer and electronic transition between Ce³⁺ and Ln³⁺ in the host material of YF₃ mesocrystals was also explored. The cytotoxicity study revealed that these YF₃-based nanocrystals are biocompatible for applications, such as cellular imaging.

Unique hematite nanochains self-assembled from α-Fe₂O₃ nanoparticles can be synthesized by thermal decomposition of [Fe₁₈S₂₅](TETAH)₁₄ as an appropriate nanoribbon precursor (TETAH=protonated triethylenetetramine). Magnetic studies have revealed greatly enhanced coercivity of the 1D hematite nanochains compared with that of dispersed α-Fe₂O₃ nanoparticles at low temperature, which may be attributed to their increased shape anisotropy and magnetocrystalline anisotropy. The photocatalytic properties of the hematite nanochains have been studied, as well as their electrochemical properties as cathode materials of lithium-ion batteries. The results have shown that both properties are dependent on the BET specific surface areas of the 1D hematite nanochains.

A magnetic, sensitive, and selective fluorescence resonance energy transfer (FRET) probe for detection of thiols in living cells was designed and prepared. The FRET probe consists of an Fe₃O₄ core, a green-luminescent phenol formaldehyde resin (PFR) shell, and Au nanoparticles (NPs) as FRET quenching agent on the surface of the PFR shell. The Fe₃O₄ NPs were used as the core and coated with green-luminescent PFR nanoshells by a simple hydrothermal approach. Au NPs were then loaded onto the surface of the PFR shell by electric charge absorption between Fe₃O₄@PFR and Au NPs after modifying the Fe₃O₄@PFR nanocomposites with polymers to alter the charge of the PFR shell. Thus, a FRET probe can be designed on the basis of the quenching effect of Au NPs on the fluorescence of Fe₃O₄@PFR nanocomposites. This magnetic and sensitive FRET probe was used to detect three kinds of primary biological thiols (glutathione, homocysteine, and cysteine) in cells. Such a multifunctional fluorescent probe shows advantages of strong magnetism for sample separation, sensitive response for sample detection, and low toxicity without injury to cellular components.

We report a first solution strategy for controlled synthesis of Adams’ catalyst (i.e., α-PtO₂) by a facile and totally green approach using H₂PtCl₆ and water as reactants. The prepared α-PtO₂ nanocrystals (NCs) are ultrasmall in size and have very “clean” surfaces, which can be reduced to Pt NCs easily in ethanol under ambient conditions. Such Adams’ catalysts have been applied as electrocatalysts beyond the field of heterogeneous catalysis. Noticeably, the water-only synthesized α-PtO₂ NCs and their derivative Pt NCs all exhibit much higher oxygen reduction reaction (ORR) activities and stabilities than that of the state-of-art Pt/C electrocatalysts. This study provides an example on the organics-free synthesis of α-PtO₂ and Pt NCs as promising cathode catalysts for fuel cell applications and, particularly, this simple, straightforward method may open a new way for the synthesis of other “clean” functional nanomaterials.

A new kind of SnO₂ nanotubes loaded with Ag₂O nanoparticles can be synthesized by using Ag@C coaxial nanocables as sacrificial templates. The composition of silver in SnO₂ nanotubes can be controlled by tuning the compositions of metallic Ag in Ag@C sacrificial templates, and the morphology of tubular structures can be changed by use of nanocables with different thicknesses of carbonaceous layer. This simple strategy is expected to be extended for the fabrication of similar metal-oxide doped nanotubes using different nanocable templates. In contrast to SnO₂@Ag@C nanocables as well as to other types of SnO₂ reported previously, the Ag₂O-doped SnO₂ nanotubes exhibit excellent gas sensing behaviors. The dynamic transients of the sensors demonstrated both their ultra-fast response (1–2 s) and ultra-fast recovery (2–4 s) towards ethanol, and response (1–4 s) and recovery (4–5 s) towards butanone. The combination of SnO₂ tubular structure and catalytic activity of Ag₂O dopants gives a very attractive sensing behavior for applications as real-time monitoring gas sensors with ultra-fast responding and recovering speed.

The removal of dye and toxic ionic pollutants from water is an extremely important issue. A simple filtration process to decontaminate water by employing a free-standing fibrous membrane fabricated from highly uniform carbonaceous nanofibers (CNFs) is demonstrated. This process combines the excellent adsorption behavior of CNFs and the advantages of membrane filtration over conventional adsorption techniques, which include simple scale-up, reduced time, and lower energy consumption. Batch adsorption experiments showed that the CNFs exhibited larger adsorption capacities than commercial granular active carbon (GAC) and carbon nanotubes (CNTs) because of their large surface area, high uniformity, and numerous active sites on the surface of nanofibers. Membrane filtration experiments proved that the CNF membranes could remove methylene blue (MB) efficiently at a very high flux of 1580 L m⁻² h⁻¹, which is 10–100 times higher than that of commercial nano- or ultrafiltration membranes with similar rejection properties. The high permeability of CNF membrane permits stacking of membranes to improve adsorption capacity. In addition, the CNF membranes are easily regenerated and remain unaltered in adsorption performance over six successive cycles of dye adsorption, desorption, and washing. Given the high adsorption and regenerability performance of the CNF membrane, it should have potential applications in water purification.

Fe₇Se₈ polyhedra with high-index facets and Fe₇Se₈ nanorods can be selectively synthesized by a solvothermal reaction in a mixed solvent of diethylenetriamine (DETA) and deionized water (DIW). It is found that the morphologies of Fe₇Se₈ nanocrystals can be effectively controlled by adjusting the volume ratio of DETA and DIW. The unusual polyhedral crystals are bounded by two {001} and twelve {012} facets. The intrinsic properties of Fe₇Se₈ nanocrystals have been investigated. Magnetic measurements indicate that the obtained polyhedra and nanorods show a weak ferromagnetic ordering at room temperature. In particular, a new photoluminescence emission at 403 nm from the Fe₇Se₈ nanocrystals has been observed. The described solvothermal reaction in a mixed solvent may be extended to the synthesis of other transition-metal chalcogenide crystals with controlled shape, facets, and structure, which may bring new functionalities.

Synthesis of coaxial nano-/microcables has been an intensive research subject due to their heterogeneous structures, tuneable properties, and important applications in nano-/micrometer-scale electronic and optoelectronic devices. Research on the fabrication of nanocables via solution strategies has made great progress in the past few years. In this Research News article, rapidly emerging new solution strategies such as hydrothermal carbonization (HTC) and synergistic soft–hard templates (SSHTs) are highlighted. Unique and flexible coaxial nano-/microcables synthesized by those methods have obvious advantages such as long-term stability and their electrical transport properties, compared with bare counterparts, suggesting that they are potential candidates as interconnects in the future.

Energy shortage, environmental crisis, and developing customer demands have driven people to find facile, low-cost, environmentally friendly, and nontoxic routes to produce novel functional materials that can be commercialized in the near future. Amongst various techniques, the hydrothermal carbonization (HTC) process of biomass (either of isolated carbohydrates or crude plants) is a promising candidate for the synthesis of novel carbon-based materials with a wide variety of potential applications. In this Review, we will discuss various synthetic routes towards such novel carbon-based materials or composites via the HTC process of biomass. Furthermore, factors that influence the carbonization process will be analyzed and the special chemical/physical properties of the final products will be discussed. Despite the lack of a clear mechanism, these novel carbonaceous materials have already shown promising applications in many fields such as carbon fixation, water purification, fuel cell catalysis, energy storage, CO₂ sequestration, bioimaging, drug delivery, and gas sensors. Some of the most promising examples will also be discussed here, demonstrating that the HTC process can rationally design a rich family of carbonaceous and hybrid functional carbon materials with important applications in a sustainable fashion.

The origin of complex superstructures of biomaterials in biological systems and the amazing self-assembly mechanisms of their emergence have attracted a great deal of attention recently. Mimicking nature, diverse kinds of hydrophilic polymers with different functionalities and organic insoluble matrices have been designed for the morphogenesis of inorganic crystals. In this Research News, emerging new strategies for morphogenesis and controlled crystal growth of minerals, that is, selective adsorption and mesoscale transformation for highly ordered superstructures, the combination of a synthetic hydrophilic polymer with an insoluble matrix, a substrate, or the air/solution interface, and controlled crystallization in a mixed solvent are highlighted. It is shown that these new strategies can be even further extended to morphogenesis and controlled crystallization of diverse inorganic or inorganic–organic hybrid materials with structural complexity, structural specialties, and improved functionalities.

Template-directed strategy has become one of the most popular methods for the fabrication of one-dimensional (1D) nanostructures with uniform size and controllable physical dimensions in recent years. This Review article describes the recent progress in the synthesis of 1D inorganic nanostructures by using suitable templates. A brief survey on the templating method based on the organic templates and porous membrane is firstly given. Then, the article is focused on recent emerging synthetic strategies by templating against the pre-existing 1D nanostructures using different physical and chemical transformation techniques, including epitaxial growth, nonepitaxial growth, direct chemical transformation, solid-state interfacial diffusion reaction, and so on. The important reactivity role of the 1D nanostructures will be emphasized in such transformation process. Finally, we conclude this paper with some perspectives and outlook on this research topic.

Multicomponent Ni₇Co₃ alloy–Au nanorings can be facilely synthesized at room temperature using metallic Ni₇Co₃ alloy nanorings as both reducing agent and sacrificial template in water. These novel alloy–Au hybrid nanorings are well biocompatible due to coating with poly(vinylpyrrolidone) and gold nanoparticles. When increasing the molar ratio of alloy to gold salt from 1:1 to 5:1, the number of the gold nanoparticles loaded on the surface of alloy nanorings were found to be decreased, and their morphology was transformed from rod to particle, remaining the ring-like assemblies. Their saturation magnetization increased due to the ring-like assemblies, resulting in the enhancement of the signal intensity in Spin–spin relaxation time (T₂) weighted magnetic resonance imaging measurement. These alloy–Au hybrid nanocomposites can perform as multimodal imaging contrast agents for cancer cell diagnosis by two-photon fluorescent imaging and T₂-weighted magnetic resonance imaging. In addition, their potential application for photothermal therapy was preliminarily investigated.

One-dimensional nanomaterials and their assemblies attract considerable scientific interest in the physical, chemical, and biological fields because of their potential applications in electronic and optical devices. The interface-assembly method has become an important route for the self-assembly of nanoparticles, nanosheets, nanotubes, and nanorods, but the self-assembly of ultralong nanowires has only been successful using the Langmuir–Blodgett approach. A novel approach for the spontaneous formation of highly aligned, ultralong Ag nanowire films at the oil–water–air interface is described. In this approach, the three-phase interface directs the movement and self-assembly process of the ultralong Ag nanowires without the effect of an external force or complex apparatus. The ordered films exhibit intrinsic large electromagnetic fields that are localized in the interstitials between adjacent nanowires. This new three-phase-interface approach is proven to be a general route that can be extended to self-assemble other ultralong nanowires and produce ordered films.

Multicomponent Ni₇Co₃ alloy–Au nanorings can be facilely synthesized at room temperature using metallic Ni₇Co₃ alloy nanorings as both reducing agent and sacrificial template in water. These novel alloy–Au hybrid nanorings are well biocompatible due to coating with poly(vinylpyrrolidone) and gold nanoparticles. When increasing the molar ratio of alloy to gold salt from 1:1 to 5:1, the number of the gold nanoparticles loaded on the surface of alloy nanorings were found to be decreased, and their morphology was transformed from rod to particle, remaining the ring-like assemblies. Their saturation magnetization increased due to the ring-like assemblies, resulting in the enhancement of the signal intensity in Spin–spin relaxation time (T₂) weighted magnetic resonance imaging measurement. These alloy–Au hybrid nanocomposites can perform as multimodal imaging contrast agents for cancer cell diagnosis by two-photon fluorescent imaging and T₂-weighted magnetic resonance imaging. In addition, their potential application for photothermal therapy was preliminarily investigated.

A simple solvothermal route in a binary solution of triethylenetetramine (TETA) and deionized water (DIW) has been used to synthesize hierarchical hollow Co₉S₈ microspheres with high surface area (80.38 m² g⁻¹). An appropriate volume ratio of TETA:DIW has been found to be essential for the formation of hollow Co₉S₈ microspheres. The magnetic study indicated that the Co₉S₈ hollow microspheres are paramagnetic at high temperature and antiferromagnetic at low temperature. The oxygen reduction reaction experiments demonstrated that the onset potential of the Co₉S₈ sample is 0.88 V, which is comparable to the value predicted for Co₉S₈ (0.74 V) from the theoretical simulation. The discharge capability of Co₉S₈ hollow microspheres as cathode materials for lithium ion batteries and their electrocatalytic activity for the oxygen reduction reaction (ORR) have been studied.

A new type of blue-light-emitting ultralong [Cd(L)(TeO₃)] (L=ethylenediamine, diethylenetriamine) nanofibre bundle has been synthesised under reflux in a mixed solvent media. Inorganic Cd(TeO₃) layers are assumed to exist in the structures and are connected by the organic amine molecules through the coordination between nitrogen atoms and cadmium ions. The composition and formulae of these hybrid materials, based on the proposed structures, have been identified through element analysis (EA), thermal gravity analysis (TGA) and energy dispersive spectra (EDS). The thermal stabilities and optical properties of these nanofibre bundles have been investigated. Thermal decomposition of [Cd(en)(TeO₃)] (en=ethylenediamine) and [Cd(DETA)(TeO₃)] (DETA=diethylenetriamine) at 450 °C allowed the formation of a mixture of CdTe and Cd(TeO₃) phases, and a pure CdTe phase, respectively. In addition, this new kind of hybrid bundle, which demonstrates blue emission, was found to be sensitive to acids, and the emission intensity is strongly dependent on the acidity of the solutions, implying that these hybrid nanofibre bundles could be potentially applied as acid sensors.

A novel method for the shape-controlled synthesis of uniformly-shaped poly(p-phenylenediamine) (PpPD) microparticles with different morphologies under ambient condition has been developed using HAuCl₄ as an oxidant and poly(N-vinylpyrrolidone) (PVP) as a surfactant. The results demonstrate that the morphologies of these microparticles can be varied from symmetrical spindle-like to diamond-like, centrosymmetric leaf-like, and parallelogram-like by tuning the concentration of reactants and their molar ratios. The length of these microparticles varies from 6 to 8 µm while the width can be tuned from 2 to 4 µm. The results demonstrate that PVP as a surfactant only plays a role in controlling the morphology of the polymer particles but has no influence on the polymer structures. UV-Vis absorption spectroscopy shows the formation of a complex between polymer ligands and lead ions by detection of new absorption peaks. Even though the as-prepared PpPD microparticles are only partly soluble, they still show an adsorptive affinity for lead ions.

Novel raft-like zinc(II)–phenylalanine complexes and zinc(II)–phenylalanine/acid green 27 (AG27) hybrid radial bundles have been successfully synthesized by a simple refluxing reaction. The formation processes of the morphologies and the superstructures of the hybrid bundles were proposed based on the time-dependent evolution process. The AG27 molecules act as both the inclusion compound and the controller of the morphologies and the superstructures of the final hybrid. The combination of the zinc(II)–phenylalanine complex and AG27 leads to distinct optical properties compared with the individual component materials. This approach opens a new and effective way for the fabrication of amino acid/dye hybrid materials with unique optical properties and is expected to allow access to other organic/organic hybrid materials with structural specificity and functional novelty.

Biocompatible and green luminescent monodisperse silver/phenol formaldehyde resin core/shell spheres with controllable sizes, in the range of 180 to 1000 nm, and interesting architectures (centric, eccentric, and coenocytic core/shell spheres) have been synthesized by a facile one-step hydrothermal approach. These spheres can be used as bioimaging labels for human lung cancer H1299 cells. The results demonstrate that the nanoparticles can be internalized into cells and exhibit no cytotoxic effects, showing that such novel biocompatible core/shell structures can potentially be used as in vivo bioimaging labels. This facile one-pot polymerization and encapsulation technique may provide a useful tool to synthesize other core/shell particles that have potential application in biotechnology.

This Feature Article provides a brief overview of the latest development and emerging new synthesis solution strategies for II–VI semiconducting nanomaterials and inorganic-organic semiconductor hybrid materials. Research on the synthesis of II–VI semiconductor nanomaterials and inorganic–organic hybrid semiconducting materials via solution strategies has made great progress in the past few years. A variety of II–VI semiconductor and a new family of [MQ(L)_0.5] (M = Mn, Zn, Cd; Q = S, Se, Te; L = diamine, deta) hybrid nanostructures can be generated using solution synthetic routes. Recent advances have demonstrated that the solution strategies in pure solvent and a mixed solvent can not only determine the crystal size, shape, composition, structure and assembly properties, but also the crystallization pathway, and act as a matrix for the formation of a variety of different II–VI semiconductor and hybrid nanocomposites with diverse morphologies. These II–VI semiconductor nanostructures and their hybrid nanocomposites display obvious quantum size effects, unique and tunable optical properties.

A new controllable homogeneous precipitation approach has been developed to synthesize zinc-substituted nickel hydroxide nanostructures with different Zn contents from a zinc nanostructured reactant. As typical layered double hydroxides (LDHs), zinc-substituted nickel hydroxide nanostructures can be formulated as NiZn_x(Cl)_y(OH)_2(1+x)−y⋅z H₂O (x=0.34–0.89, y=0–0.24, z=0–1.36). The structure and morphology of zinc-substituted nickel hydroxide nanostructures can be systematically controlled by adjustment of the zinc content. The effects of temperature and the amounts of ammonia and zinc nanostructured precursor on the reaction were systematically investigated. In our new method, although zinc-substituted α-and β-nickel hydroxides have the typical 3D flowerlike architecture and stacks-of-pancakes nanostructures, respectively, their growth processes are different from those previously reported. A coordinative homogeneous precipitation mechanism is proposed to explain the formation process of zinc-substituted nickel hydroxide nanostructures. The zinc-substituted nickel hydroxide nanostructures exhibit some interesting intrinsic properties, and changing the zinc content can effectively tune their optical, magnetic, and electrical properties.

Nanoporous VSB-5 nickel phosphate molecular sieves with relatively well controllable sizes and morphology of microspheres assembled from nanorods were synthesized at 140 °C over a short time in the presence of hexamethylenetetramine (HMT) by a facile hydrothermal method. The pH value, reaction time, and ratio of HMT to NaHPO₂⋅H₂O crucially influence the morphology and quality of the final products. By adjusting the pH value of the initial reaction solution, the morphology changes from disperse rods to microspheres assembled from rods and finally to a large quantity of fibers, and the diameters of the VSB-5 rods can be varied. The catalytic activity of VSB-5 in selective hydrogenation of several unsaturated organic compounds was tested. Nickel(II) in VSB-5 can selectively catalyze hydrogenation of CC in trans-cinnamaldehyde and 3-methylcrotonaldehyde. In addition, since nitrobenzene (NB) and 2-chloronitrobenzene could be reduced to aniline (AN) and 2-chloroaniline with high selectivity, VSB-5 could have potential applications in synthesizing dyes, agrochemicals, and pharmaceuticals.