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Graphene quantum dots (GQDs) are attractive fluorescent nanoparticles that have wide applicability, are inexpensive, nontoxic, photostable, water-dispersible, biocompatible and environmental-friendly. Various strategies for the synthesis of GQDs have been reported. However, simple and efficient methods of producing GQDs with control over the size of the GQDs, and hence their optical properties, are sorely needed. Herein, an ultra-fast and efficient laser writing technique is presented as a means to produce GQDs with homogeneous size from graphene produced by the instantaneous photothermal gasification and recrystallization mechanism. Controlling the laser scan speed and output power, the yield of GQDs can reach to be about 31.458 mg/s, which shows promising potential for large-scale production. The entire process eliminates the need for chemical solvents or any other reagents. Notably, the prepared laser writing produced GQDs (LWP-GQDs) exhibit blue fluorescence under UV irradiation of 365 nm and the Commission Internationale de L’Eclairage (CIE) chromaticity coordinates is measured at (0.1721, 0.123). Overall, this method exhibits superior advantages over the complex procedures and low yields required by other existing methods, and thus has great potential for the commercial applications.

MXene is a neoteric type of bidimensional (2D) transition metal carbide/nitride with broad application prospects, in particular with electrochemical energy storage. The electrochemical performance of MXene is unsatisfactory because it is easy to stack resulting in the difficulty of electrolyte penetration and ion transport. In this study, the cobaltous sulfide-modified 3D MXene/N-doped carbon foam (CoS@MXene/CF) hybrid aerogel is projected and manufactured via simple in situ growth and thermal annealing strategies. The capacitance of the as-fabricated 300-CMC-31:1 electrode material reaches 250 F g-1 (1 A g-1), which is obviously higher than those of MXene, CoS@CF, 400-CMC-31:1, 300-CMC-10:1, 300-CMC-50:1, CF, and MXene/CF electrode materials. Moreover, it can hold 97.5% of the original capacitance after 10,000 cycles and the internal resistance (Rs) is only 0.50 Ω. A green bulb can be lit by two all-solid asymmetric supercapacitors installed in series. The prepared CoS@MXene/CF hybrid aerogel exhibits promising potential for practical application in energy storage areas.

Layered double hydroxides (LDHs) are a kind of classic pseudocapacitive materials with lamellar structure and large specific surface area, which have attracted swinging attention in the electrochemical energy storage area. The CoS2@Ni is synthesized through a hydrothermal process, followed by surface generation of the flower-like nickel-iron layered double hydroxide (NiFe-LDH) nanospheres through a hydrothermal process, which is directly used to design a binder-free electrode with a splendid capacitance capability. The as-synthesized NiFe-LDH@CoS2@Ni electrode presents an outstanding specific capacitance of 11.28 F cm-2 (3880 F g-1) at 2 mA cm-2 (1.17 A g-1) in a three electrodes system. Also, the all-solid-state asymmetric supercapacitor (ASC) is combined utilizing the NiFe-LDH@CoS2@Ni hybrid as the positive electrodes and active carbon covered Ni foam as negative electrodes, respectively. The as-fabricated ASC exhibits a high energy density of 15.84 Wh kg-1 at the power density of 375.16 W kg-1 and can be able to lighten a blue LED indicator for more than 30 minutes, revealing that the prepared NiFe-LDH@CoS2@Ni owns great potential in the aspect of practical applications. Therefore, the prepared NiFe-LDH@CoS2@Ni with outstanding electrochemical properties could be applied for high-performance supercapacitors.

NiCo-LDH has attracted increasing attention in recent years for application in supercapacitors (SCs) owing to its high redox activity and intercalating capability. However, the pristine NiCo-LDH is...

Supercapacitors have attracted tremendous research interest, since they are expected to achieve battery-level energy density, while having a long calendar life and short charging time. Herein, a novel asymmetric supercapacitor has been successfully assembled from NiCo2 S4 nanosheets and spinous Fe2 O3 nanowire modified hollow melamine foam decorated with polypyrrole as positive and negative electrodes, respectively. Owing to the well-designed nanostructure and suitable matching of electrode materials, the assembled asymmetric supercapacitor (ASC) exhibits an extended operation voltage window of 1.6 V with an energy density of 20.1 Wh kg-1 at a power density of 159.4 kW kg-1 . Moreover, the ASC shows stable cycling stability, with 81.3 % retention after 4000 cycles and a low internal resistance of 1.03 Ω. Additionally, a 2.5 V light-emitting diode indicator can be lit up by three ASCs connected in series; this provides evidence of the practical application potential of the assembled energy-storage system. The excellent electrochemical performances should be credited to the significant enhancement of the specific surface area, charge transport, and mechanical stability resulting from the unique 3D morphology.

A fiber asymmetric supercapacitor system is designed with NiCo-LDH nanoflakes and FeOOH nanosheets anchored on electrochemically activated graphite fibers as positive electrode and negative electrode, respectively. Due to the formation of C O Metal bonding, the oxygen-functionalized carbon on electrochemically activated graphite fibers can bind strongly with NiCo-LDH and FeOOH, which assists in establishing the fast electron transfer routes and fluent ion transport avenues. Both NiCo-LDH and FeOOH anchored on electrochemically activated graphite fibers display a high rate performance, 80% and 87.3% of the electric capacity can be reserved with the current density increasing from 2 to 20 A g−1 and 2 to 10 A g−1, respectively, while the NiCo-LDH and FeOOH deposited on untreated graphite fibers can only retain 45% and 40%. The fabricated novel solid-state fiber asymmetric supercapacitor device exhibits an expanded operation potential window of 1.8 V with a maximum energy density (130 W h kg−1) when the power density is 1.8 kW kg−1. Furthermore, a high energy density (81 W h kg−1) is still achieved at a superhigh power density (10.8 kW kg−1). Additionally, a good cycling stability of the solid-state fiber asymmetric supercapacitor can be obtained (90% capacity retention after 10,000 cycles).

Aqueous Zinc-ion batteries (ZIBs), using zinc negative electrode and aqueous electrolyte, have attracted great attention in energy storage field due to the reliable safety and low-cost. A composite material comprised of VO2·0.2H2O nanocuboids anchored on graphene sheets (VOG) is synthesized through a facile and efficient microwave-assisted solvothermal strategy and is used as aqueous ZIBs cathode material. Owing to the synergistic effects between the high conductivity of graphene sheets and the desirable structural features of VO2·0.2H2O nanocuboids, the VOG electrode has excellent electronic and ionic transport ability, resulting in superior Zn ions storage performance. The Zn/VOG system delivers ultrahigh specific capacity of 423 mAh·g−1 at 0.25 A·g−1 and exhibits good cycling stability of up to 1,000 cycles at 8 A·g−1 with 87% capacity retention. Systematical structural and elemental characterizations confirm that the interlayer space of VO2·0.2H2O nanocuboids can adapt to the reversible Zn ions insertion/extraction. The as-prepared VOG composite is a promising cathode material with remarkable electrochemical performance for low-cost and safe aqueous rechargeable ZIBs.

Flexible electronic devices constitute a rapidly rising industry since they can potentially renovate the way humans communicate and interact with external environments. Recently, flexible fiber-shaped supercapacitors have shown great potential in wearable and portable electronics. Herein, a new type of flexible coaxial fiber-shaped asymmetric supercapacitor (FASC) is successfully constructed utilizing a well-aligned Mn, Ni co-substituted Co carbonate hydroxide nanoneedle array on a carbon fiber (MnNiCo-CH/CF) as the positive electrode and an activated carbon (AC) as the negative electrode. Impressively, the MnNiCo-CH/CF electrode with a hierarchical nanostructure exhibits a high specific capacitance of 1440.52 F g−1 at 1 A g−1 and superb cycling stability (90.78%), while the as-fabricated coaxial FASC exhibits a large specific capacitance of 96.13 F g−1 (1 A g−1) and a high energy density of 30.04 W h kg−1 at a power density of 749.97 W kg−1. Moreover, the integration of a few FASCs in series or in parallel is demonstrated to meet the energy and power needs in various practical applications, such as powering shunt-wound LEDs or stitching into cotton fabrics to charge LED electronic displays. Therefore, the successful fabrication of practicable and ultra-flexible FASCs may realize broad applications in future flexible energy storage devices.

The development for environmentally friendly energy conversion and storage equipment has given rise to tremendous research efforts as a result of the growing requirements for environmental friendly resources and the rapid consumption of traditional fossil fuel. Herein, a novel hierarchical CoO/NiO-Cu@CuO heterostructure is successfully devised and synthesized. Cobalt/nickel ions are used to generate novel CoO/NiO-doped laminated CuO nanospheres through the facile in situ wet oxidation combined with cation exchange and calcination strategies. As a result, the electrochemical supercapacitance of the as-prepared CoO/NiO-Cu@CuO electrode can reach 875 C cm-2 (2035 mF cm-2), which exhibits much better electrochemical performance compared to other precursor electrodes at a same current density of 2 mA cm-2. Moreover, an excellent rate capacity of 1395 mF cm-2 (50 mA cm-2) can be achieved when measured at a relative high current density; 90.3% of the initial supercapacitance remains even after 5000 cycles. Furthermore, the as-prepared hierarchical hybrid of laminated CoO/NiO-CuO nanospheres in situ generated on three-dimensional (3D) porous Cu foam is applied to prepare a solid-state asymmetric supercapacitor equipment unit. The fabricated equipment unit shows an energy density of 69.3 W h kg-1 at a power density of 1080 W kg-1. Additionally, the commercially applied 2.5 V light-emitting-diode indicator with blue light can be energized for 4 min when two as-fabricated supercapacitor devices are in series connection. The unique hierarchical heterostructure of the novel laminated nanospheres combined with the 3D grid structure brings about the outstanding electrochemical capacitor performances. This strategy for the fabrication of hierarchical heterostructure electrodes could have an enormous potential for high-performance electrochemical equipment.

Compressible and flexible supercapacitors have aroused enormous interest of many scientific researchers for potential applications in wearable electronic products. However, the design and construction of the electrode with superior mechanical as well as electrical properties still face a lot of challenges. In present work, melamine foam/polypyrrole (MF/PPy) electrode with high deformation-tolerance and excellent electrochemical performance is prepared by in-situ interfacial polymerization of polypyrrole on commercial melamine foam, where PPy nanoparticles with size of 700 nm are uniformly anchored on the MF skeletons. The electrochemical characterizations show that the electrode exhibits excellent specific area capacitance of 2.685 F cm−2 at 2 mA cm−2 and good cyclic stability with more than 80% of capacitance remained after 3000 cycles. Furthermore, a symmetrical aqueous supercapacitor is assembled and exhibits an excellent energy density up to 75.95 μWh cm−2 at the power density of 5.82 mW cm−2 and excellent cycling stability as the current density increases by 10 times. Even under a high strain of 70%, about 95.76% of the initial capacitance is retained after 500 consecutive compressions. These outstanding performances enable the MF/PPy composite a promising candidate for potential applications in compressible and flexible electrochemical energy storage devices.

To achieve high catalytic activity and stability with low noble-metal loadings on green and natural supports has attracted tremendous attention in the past few years. Herein, a facile strategy is exploited to synthesize Au nanoclusters (with size of ∼1.4 nm) which are homogeneously distributed on carbonized natural lotus leaf sheets with less mass. Compared to the pure AuNCs, the AuNCs@carbonized lotus leaf (AuNCs@C-lotus leaf) micro/nanohybrid with the unique papillae structures and large surface area not only exhibits better catalytic activity for the reduction of 4-nitrophenol (4-NP), but also prevent the aggregation of AuNCs. In addition, the catalytic performance of AuNCs@C-lotus leaf catalyst increased with the temperature increasing of the reaction temperature. Moreover, the AuNCs@C-lotus leaf catalyst can be packed into a filtering platform to fabricate a fixed-bed system, with which the catalytic conversion could reach 71.7% for 0.2 mM 4-NP solution that pass through at flow rate of 1 mL/min. Furthermore, the AuNCs@C-lotus leaf catalyst shows excellent recyclability and only slight loss of catalytical activity is observed after recycling for five successive times. This mild and environmental friendly methodology could be generalized to the synthesis of other metallic nanoparticles@carbonized botanical leaf micro/nanohybrids as promising heterogeneous catalysts for varied catalytic reactions.

Recently, ternary cobalt nickel sulfide, performing as the promising electrode material for supercapacitors has obtained great interests. Herein, the hollow and spinous NiCo2S4 nanotubes are designed and prepared through a simple hydrothermal reaction using the natural silk as the template. The spinous Ni-Co precursors are grown on the natural silk through a facile hydrothermal strategy and the hollow structure is obtained by decomposing the silk via hydrothermal sulfurization. After the calcination treatment, the hollow and spinous NiCo2S4 nanotubes are applied as the electrode material and exhibit better electrochemical performance than the solely vulcanized samples. In addition, owing to the unique hollow and spinous structure of NiCo2S4 nanotubes, the supercapacitor electrode material shows good specific capacitance (630 F g−1 at 1 A g−1), low internal resistance Rs (0.68 Ω) and high capacitance retention (91% after 3000 cycles) at 10 A g−1. Furthermore, an all-solid-state asymmetric supercapacitor is self-assembled with the SC400 composite and exhibits an energy density of 52.34 Wh kg−1 at the power density of 2206.37 W kg−1. Additionally, a blue LED indicator can be powered by connecting two ASCs in series. The prepared hollow and spinous NiCo2S4 nanotubes with excellent electrochemical properties can envision promising applications in energy storage devices and nanotechnology.

Here, two-dimensional (2D) C/TiO2 hybrids synthesized via oxidation of Ti3C2Tx MXenes are reported as an ideal electrorheological (ER) candidate in pursuit of high ER efficiency. The lamellar struc...

The clinical applications of a large variety of inorganic nanomaterials have been severely limited by their long-term retention with potential toxicity in the body. Herein, we develop a self-guided photothermal nanocarrier based on MoS2 nanodots (MoS2 NDs) modified with copolymer P(OEGA-co-VBA) and targeting ligands of transferrin (Tf). The copolymer P(OEGA-co-VBA) is synthesized via RAFT polymerization and not only utilized to improve the biocompatibility of MoS2 NDs, but also efficiently load the drug doxorubicin (DOX) via acid-cleavable Schiff base bonds. Besides, thiol functionalized transferrin (Tf-SH) is anchored onto the surface of MoS2 NDs via the formation of disulfide bonds, which could further enhance the cellular engulfed of MoS2 NDs nanocarrier to HepG2 cells. The as-prepared nanocarrier is stable in physiological condition while quickly release drug upon the synergistic trigger of acidic pH and glutathione (GSH). Moreover, the modified MoS2 (DOX-POV-MoS2-Tf) nanoagents shows better therapeutic effect probably attributed to the synergistic effects of targeted uptake, pH, GSH and NIR induced localized heating, which suggest the designed MoS2 nanocarrier is promising for applications in multi-modal biomedical therapy.

Discovering the relationship of structure and rheological behaviors remains challenging. In this study, the TiO2 nanoparticle decorated magnetic MoS2 nanosheets (Fe3O4@MoS2@TiO2 nanoparticles) exhibited unique rheological behaviors under external electric and magnetic fields owing to their special hierarchical structures. The constructed core–shell structures of the Fe3O4@MoS2@TiO2 nanoparticles were confirmed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The magnetic behaviors were studied using a vibrating sample magnetometer (VSM). The Fe3O4@MoS2@TiO2 nanoparticles exhibited both electrorheological (ER) and magnetorheological (MR) properties that result from the decoration of high dielectric TiO2 nanoparticles on the MoS2 shell and paramagnetic behavior of Fe3O4 nanoparticles in the core, respectively. The MoS2 nanosheets act as superb lubricant at a high shear rate due to their weak interlayer van der Waals forces. The abrupt decrease of shear stress at a critical shear rate was observed under the external magnetic field and the proposed mechanism was also discussed. The unique rheological behaviors of the Fe3O4@MoS2@TiO2 nanoparticle based suspensions highlight the great promise of MoS2-based materials for cornerstone applications in rheological fields.

Glucose oxidase (GOx), traditionally regarded as an oxidoreductase with high β-D-glucose specificity, has been widely applied as sensing probe for β-D-glucose detection. However, it is found that the specificity of GOx is not absolute and GOx cannot decern β-D-glucose among its isomers such as xylose, mannose and galactose. The existence of the other monosaccharides in sensing system could compromise the sensitivity for β-D-glucose, therefore, it is of great urgency to achieve the highly specific catalytic performance of GOx. Herein, porous metal-organic frameworks (MOF) are prepared as the host matrix for immobilization of both GOx and bovine hemoglobin (BHb), obtained a cascaded catalytic system (MOF@GOx@BHb) with both enhanced GOx activity and peroxidase-like activity owing to the spatially confined effect. Then, using β-D-glucose as both template molecules and substances, hydroxyl radicals are produced continuously and applied for initiating the polymerization of molecular imprinting polymers (MIPs) on the surface of MOF@GOx@BHb. Impressively, the obtaining molecularly imprinted GOx (noted as MOF@GOx@BHb-MIPs) achieves the highly sensitive and specific detection of β-D-glucose in the concentration range of 0.5–20 μM with the LOD = 0.4 μM (S/N = 3) by colorimetry. Similarly, MOF@GOx@BHb-MIPs are subsequently obtained using mannose, xylose and galactose as template molecules, respectively, and also show satisfied specific catalytic activity towards corresponding templates, indicating the effectiveness of the proposed strategy to achieve highly specific catalytic performance of GOx.

Novel nanomaterials and advanced nanotechnologies continue to promote the fast development of new approaches for efficient tumor therapy. As an alternative choice to various traditional therapies, non-invasive photothermal therapy (PTT) has attracted significant attention mainly due to its low cost, highly localizing, specific tumor treatment and minimal side effects on healthy tissues. PTT induced by photo-absorbing agents which can absorb and convert the external NIR laser into heat to ablate tumors. Plenty of studies have shown the significant potential of PTT to treat tumors in future practical applications. However, PTT alone usually could not eradicate tumors considering the intensity of laser gradual attenuates in biological tissues and the heat generated tends to distribute inhomogeneous within tumors tissues. Combination of chemotherapy with photothermal therapy into one system for tumor therapy is an effective strategy to further improve the therapy efficiency. In this Minireview, we focus on the recent advances in constructing PTT therapeutic and multi-model combination therapeutic via integrating nanomaterials and functional polymers.

Molybdenum disulfide (MoS2 ) nanosheets have attracted significant attention due to their photothermal properties, but the poor solubility and colloidal stability limited their further application in biomedical field. Here, we report a targeted photothermal controllable nanocarrier consisting of MoS2 nanosheets modified with block copolymer P(OEG-A)-b-P(VBA-co-KH570) and targeting ligand transferrin. P(OEG-A)-b-P(VBA-co-KH570) is synthesized by RAFT polymerization and utilized not only to improve the solubility of MoS2 nanosheets but also efficiently load the anti-cancer drug doxorubicin (DOX) through an acid-cleavable Schiff base linker. Thiol-functionalized transferrin (Tf-SH) is anchored onto the surface of MoS2 nanosheets by the formation of disulfide bonds, which could further enhance the cellular uptake of DOX and MoS2 to HepG2 cells for high-efficiency synergetic therapy. The drug release experiments exhibited the minimal release of DOX at room temperature and neutral pH, and the maximal drug release of 53 % at acidic tumor pH and hyperthermia condition after 48 h. In addition, the DOX-loaded, Tf-SH and P(OEG-A)-b-P(VBA-co-KH570) modified MoS2 (DOX-POVK-MoS2 -Tf) showed better a therapeutic effect than DOX-POVK-MoS2 and POVK-MoS2 , probably owing to the combined effects of target-directed uptake, acid-triggered drug release, and NIR induced localized heating, which suggest the designed MoS2 nanocarriers are promising for applications in multi-modal cancer therapy.

Near-infrared (NIR) light possesses great advantages for light-responsive controllable drug release, such as deep tissue penetration and low damage to healthy tissues. Herein, a targeted and NIR-triggered drug delivery system is developed based on a NIR dye, indocyanine green (ICG), and anticancer drug, doxorubicin hydrochloride (DOX)-loaded thermo-responsive block copolymer capsule, in which the drug release can be controlled via NIR irradiation and folic acid (FA) molecule endows the drug carrier with the ability of targeted receptor-mediated endocytosis. After co-encapsulation of DOX and ICG, the capsule carrier exhibited wider NIR absorption peak and the loaded DOX was released rapidly from the capsules upon irradiation by NIR laser (808 nm). In addition, the results demonstrated that the FA modified capsule carrier exhibited the higher cytotoxicity to HeLa cells with NIR irradiation compared with other treatments, indicating the efficient chemo-photothermal targeted therapy.

To improve cancer therapeutic efficacy and avoid side effects on normal tissues, a targeted chemo–photothermal nanoplatform was designed based on transferrin-decorated and MoS2-capped hollow mesoporous silica nanospheres. MoS2 nanosheets acted as a gatekeeper to prevent the leakage of DOX from the drug delivery system as well as the photothermal agent (PTA) to improve the therapeutic effect and facilitate the NIR-triggered endosomal escape. In this work, MoS2 nanosheets were anchored on the surface of hollow mesoporous silica nanospheres (HMSNs) via the formation of disulfide bonds (–S–S), which could be easily cleaved in the presence of the intracellular GSH, leading to stimuli-responsive drug release from the hollow mesoporous silica nanocarriers. Moreover, to further improve the tumor specificity and cellular uptake of the anti-cancer drug, the nanocarrier surface was also modified with the targeting ligand transferrin via –S–S linkage. The results demonstrated that the transferrin-decorated, MoS2-capped HMSNs can be utilized as a targeting chemo–photothermal synergetic system with high therapeutic efficacy.

Freestanding electrodes fabricated with hierarchical core-shell micro-/nano-structured materials synthesized from redox-type metal oxides show enormous potential for portable electronic devices. In this, a novel and facile strategy for the preparation of petaloid and origami-lantern shaped MnO2/Co2CH@C hierarchical porous core-shell nanorod arrays is proposed. The fabricated electrode based on MnO2/Co2CH@C hybrid composite exhibits superior capability of 2022 mF cm−2 under high current density of 5 mA cm−2, which can be explained by the well-oriented petal-like and origami-lantern shaped nanosheets as well as the 3D core-shell porous hierarchical structure. Additionally, a solid-state asymmetric supercapacitor equipment is assembled on basis of the synthesized hierarchical MnO2/Co2CH@C hybrid, exhibiting an energy density of 15 Wh kg−1 at the power density of 255 W kg−1. Notably, the multifunctional instrument can be operated by the assembled device for 8 min, while monitoring time, temperature and air humidity in a portable outdoor environment. Moreover, a blue indicator can also be operated for 9 min long, evidencing their potential commercial applications. Overall, this work demonstrates the promising potential of the synthesized novel origami-lantern shaped and highly oriented hierarchical composites for electrochemical energy storage applications.

Recently, elemental doping has proven to be an efficient method to improve the electrochemical performance of nanomaterials. In this work, we successfully synthesized Ni1-xCoxMoO4 with tunable morphologies through Co-doping by a facile chemical co-precipitation method, among which Ni0.85Co0.15MoO4 displays an excellent specific capacitance (1301 F g−1 at 1 A g−1), which is higher than NiMoO4 electrode (1050.4 F g−1 at 1 A g−1) and Ni0.7Co0.3MoO4 electrode (755.2 F g−1 at 1 A g−1). In addition, Ni0.85Co0.15MoO4 electrode shows excellent cycling stability with 86% retention of its original capacitance after 3000 cycles. Additionally, an asymmetric supercapacitor (ASC) device can be fabricated using Ni0.85Co0.15MoO4/nickel foam (Ni0.85Co0.15MoO4/NF) as positive electrode and active carbon/nickel foam (AC/NF) as negative electrode. The as-fabricated ASC achieves a high energy density of 37.26 Wh kg−1 at the power density of 400 W kg−1, highlighting its potential application for the efficient energy storage devices.

Mesoporous carbon nanoparticles (MCNs) were prepared through a series of annealing procedures using well-controlled diblock copolymer micelles as precursors. The micelles were prepared from poly(acrylonitrile)-block-poly(methylmethacrylate) (PAN-b-PMMA), and synthesized via reversible addition–fragmentation chain transfer (RAFT) polymerization. The RAFT-controlled synthesis of block copolymer, PAN-b-PMMA was conducted either in solution or emulsion conditions. It was found that micelles with well-defined morphology could be directly formed from the emulsion polymerization. The as-synthesized micelles containing hydrophilic PAN corona as the carbon source and hydrophobic PMMA core as the sacrificing template underwent a microphase-separation process to form a nanostructure at 250 °C, followed by carbonization at 800 °C to afford MCNs. What's more, the MCNs based supercapacitor exhibited a good capacitance value of 220 F g−1 and an excellent cycling performance of 91% capacitance retention after 10000 cycles. The as-prepared MCNs are envisioned to provide broad practical applications in the fields of energy storage and nanotechnology.

Nanostructured carbon materials have shown promising applications for energy storage because of their high capacitive characteristic. However, developing three-dimensional (3D) hierarchical carbon materials with both high compressibility and capacitance is still challenging. Herein, we report the fabrication of hierarchical polypyrrole (PPy)/graphene (reduced graphene oxide (G) and holey reduced graphene oxide (h-G))/melamine composite foam through a simple template method. By systematically optimizing the mass ratios of the G/h-G and the sizes of the PPy nanoparticles (PPy NPs), the as-prepared composite electrode displays a gravimetric capacitance of 422.6 F g−1 at a current density of 0.5 A g−1. Due to the interconnected h-G/G network and elastic melamine foam (MF) skeleton, the as-prepared composite electrode also shows compressible performance, which can be compressed to a strain of 60% and completely recover to its original shape when released. When the composite electrodes are assembled to a compressible supercapacitor which shows a stable capacitance under different compressive strains (0%, 25%, 50% and 75%) and a long-term compression test at 50% strain for 100 cycles. Therefore, the successful preparation of compressible composite electrode should open many opportunities in compressible and durable energy storage devices.

Supercapacitors are attracting tremendous research interest because they are expected to achieve battery-level energy density while having long calendar life and short charging time. Ultrathin layered double hydroxide nanosheets (LDHs) are promising candidates as electrode materials for energy storage. Herein, we have successfully designed and synthesized a hierarchical NiMn-LDH@CuO/CF core-shell heterostructure which comprises a vertical and intercrossing ultrathin NiMn-LDHs nanosheets shell and a slightly curly and tops tangled CuO nanowires core. The synthesized NiMn-LDH@CuO/CF electrode exhibits a high areal capacitance of 6077 mF cm−2 (2430.8 F g−1) at a current density of 2 mA cm−2 (0.8 A g−1), which is significant higher than those of CF, Cu(OH)2/CF, CuO/CF, NiMn-LDH/CF and NiMn-LDH electrodes. Moreover, a superior cycling stability of 89.22% retention after 8000 cycles at a high current density of 50 mA cm−2 is observed and a low internal resistance Rs (0.584 Ω) can be achieved. Furthermore, an all solid-state asymmetric supercapacitor (ASC) device based on the as-synthesized hierarchical NiMn-LDH@CuO/CF core-shell heterostructure hybrid material as positive electrode and activated carbon as negative electrode is successfully fabricated and exhibits an energy density of 10.8 W h kg−1 at a power density of 100 W kg−1. Additionally, a LED indicator can be lit up for eight minutes when three ASCs are connected in series. The excellent electrochemical performances can be credited to the significant enhancement of the specific surface area, charge transport and mechanical stability resulted from the ultrathin LDH shell, the highly conductive CuO nanowires core-shell nanostructure. This strategy for the fabrication of hierarchical core-shell heterostructure could have enormous potential for applications in high performance energy storage devices.

MXenes are a new family of 2 D transition metal carbides and nitrides, which have attracted enormous attention in electrochemical energy storage, sensing technology, and catalysis owing to their good conductivity, high specific surface area, and excellent electrochemical properties. In this work, a series of Co3 O4 -doped 3 D MXene/RGO hybrid porous aerogels is designed and prepared through a facile in situ reduction and thermal annealing process, in which the reduced graphene oxide (RGO) conductive network can electrically link the separated Co3 O4 -MXene composite nanosheets, leading to enhanced electronic conductivity. It is found that upon using the Co3 O4 -MXene/RGO hybrid porous aerogel prepared with a mass ratio of Co3 O4 -MXene/RGO of 3:1 (CMR31) as an electrode for a supercapacitor, a superior specific capacitance of 345 F g-1 at the current density of 1 A g-1 is achieved, which is significantly higher than those of Ti3 C2 Tx MXene, RGO, and MXene/RGO electrodes. In addition, a high capacitance retention (85 % of the initial capacitance after 10 000 cycles at a high current density of 3 A g-1 ) and a low internal resistance Rs (0.44 Ω) can be achieved. An all-solid-state asymmetric supercapacitor (ASC) device is assembled using CMR31, and it has the ability to light up a blue LED indicator for 5 min if four ASCs are connected in series. Therefore, these novel Co3 O4 -MXene/RGO hybrid porous aerogels have potential practical applications in high-energy storage devices.

In this review, we focus on recent advances in the synthesis of polymer-functionalized transition-metal-based nanomaterials and follow this up by discussing their applications in bioimaging diagnosis and cancer therapy. Transition-metal-based nanomaterials show great potential in cancer therapy owing to their intensive near-IR absorption, excellent photothermal conversion efficiency, strong X-ray attenuation, and magnetic properties. Functional polymers are usually introduced by a one-step or multistep method to further endow these nanomaterials with great biocompatibility and physiological stability. Polymer-decorated transition-metal nanomaterials show great potential in multimodal imaging diagnosis (photoacoustic imaging, computed tomography, photoluminescence imaging, positron emission tomography, etc.) and cancer therapy (chemotherapy, photothermal therapy, microwave therapy, radiotherapy, photodynamic therapy). At the end of this review, the prospects of these polymer-decorated transition-metal-based nanomaterials are also discussed.

Cancer gives rise to an enormous number of deaths worldwide nowadays. Therefore, it is in urgent need to develop new therapies, among which combined therapies including photothermal therapy (PTT) and chemotherapy (CHT) using polymer-based nanocarriers have attracted enormous interest due to the significantly enhanced efficacy and great progress has been made so far. The preparation of such nanocarriers is a comprehensive task involving the cooperation of nanomaterial science and biomedicine science. In this review, we try to introduce and analyze the structure, preparation and synergistic therapeutic effect of various polymer-based nanocarriers composed of anti-tumor drugs, nano-sized photothermal materials and other possible parts. Our effort may bring benefit to future exploration and potential applications of similar nanocarriers.

Graphene, as a new emerging carbon material, has attracted significant attention due to its remarkable properties, such as excellent electrical and thermal conductivity, fast mobility of charge carriers, high fracture strength, and large specific surface area. As the most promising carbonaceous nanofillers, graphene-based nanocomposite fibers have promoted the fast development of fibrous materials for emerging applications in need of superior mechanical, thermal, electrical, optical, antibacterial, or adsorption performance. In this comprehensive chapter, the commonly applied strategies to prepare and modify graphene and graphene-reinforced polymer fibers are briefly introduced. Then, the properties of the graphene/polymer nanocomposite fibers are summarized and discussed in detail, including mechanical properties, electrical conductivity, thermal properties, and other properties. Finally, the applications of the graphene/polymer nanocomposite fibers are also highlighted in brief.

Promoted by recent advances in developing nanomaterials and drug delivery, stimuli-responsive polymer systems that can remotely trigger drug release in a spatiotemporal manner has attracted significant attention in biotechnology. Implementation of remote-controlled release requires functional polymers to be susceptible to specific physical and/or chemical stimuli. In this minireview, we focus on the recent advances in the construction of stimuli-responsive polymer systems for remotely controlling drug release in response to an externally applied stimulus (light, microwave, magnetic field, electric field and ultrasound). The design of the stimuli-responsive polymer systems and formulations to remotely control the release of drug molecules is also highlighted in this minireview. Furthermore, the potential in biomedical applications and the perspectives of future developments of these stimuli-responsive polymer systems are also briefly discussed.

The hierarchical nanostructure hybrids of porous Co3O4 nanowires coated NiMn layered double hydroxide nanosheets array on Ni foams (Co3O4@NiMn-LDH/Ni) are designed and prepared via the two-step hydrothermal reactions with a combination of annealing process. The Co3O4 nanowires can be utilized as backbone to grow the NiMn-layered double hydroxide (NiMn-LDH) nanosheets, which provide a large surface area and leading to the enhanced capacitive performance owing to the effective ion/electron diffusion rates. The areal capacitance of the as-prepared Co3O4@NiMn-LDH/Ni electrode reaches 19.7 F cm−2 (5419.7 F g−1) at 2 mA cm−2 (0.56 A g−1). Moreover, a high capacitance retention (93.25% of capacitance maintained after 6000 cycles) and a low internal resistance Rs (0.62 Ω) can be acquired. Additionally, an all-solid-state asymmetric supercapacitor (Co3O4@NiMn-LDH/Ni//AC ASC) based on the Co3O4@NiMn-LDH/Ni as positive electrode and activated carbon (AC) as negative electrode is successfully obtained. The Co3O4@NiMn-LDH/Ni//AC ASC shows a high energy density of 47.15 Wh kg−1 at 376 W kg−1. Additionally, a LED can be lit up for 12 min when three ASCs are connected in series. Therefore, this novel Co3O4@NiMn-LDH/Ni with outstanding electrochemical performance should envision potential practical applications in high energy storage appliances.