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To replace the current expensive precious metal catalysts for water electrolysis, it is important to develop inexpensive and powerful bifunctional catalysts for hydrogen production. It is an effective way to improve catalytic performance using excellent templates and elemental doping. Here, a hierarchical structure Fe-Co3S4/MoS2 was synthesized using an Fe–ZIF precursor prepared by ion exchange, followed by hydrothermal sulfuration and annealing. It required overpotentials of only 93 mV and 243 mV to achieve a current density of 10 mA cm−2 in the HER and OER, respectively. It also showed excellent catalytic performance for overall water splitting, requiring only 1.42 and 1.71 V to achieve current densities of 10 and 100 mA cm−2 in 1 M KOH. The catalyst also demonstrated excellent ultra-long-term stability. The superb catalytic performance and stability can be attributed to the Fe doping, exposing more active sites while retaining the highly stable framework of the ZIF. The component modulation of Co3S4 and MoS2 by Fe doping induced high intrinsic activity and excellent transfer coefficients. This work presents a novel approach to prepare noble metal-free catalysts with highly stable rich interfaces and defects for overall water splitting. [ABSTRACT FROM AUTHOR]

Developing noble-metal-free bifunctional electrocatalysts at an effective cost and with a high catalytic ability for hydrogen production via water-splitting is imperative, although a great bottleneck remains. Herein, we present a plasma engraving strategy to synthesize N-doped CoFeS on cobalt foam with a multi-interface and defect hierarchical structure. The N-doped CoFeS was synthesized using an ion exchange method to prepare the CoFe LDH precursor, followed by sulphidation and plasma-assisted engraving in nitrogen gas. The N-doped CoFeS requires an overpotential of 230 mV for the OER and 26 mV for the HER to reach a current density of 10 mA cm−2. It also shows an excellent catalytic activity towards overall water splitting, which requires a low voltage of 1.61 and 1.80 V to achieve a current density of 10 and 50 mA cm−2, respectively, in 1 M KOH. The super-catalytic properties can be attributed to the interface and defect structure, which induces a high intrinsic activity, a superior transfer coefficient, and abundant active sites. This work presents a novel approach to prepare noble-metal-free electrocatalyst with plenty of interface and defect sites for overall water splitting. [ABSTRACT FROM AUTHOR]

Herein, we synthesize 3D nanoflower-like MCo2O4@MCo2S4@polypyrrole (M = Cu, Mn) core–shell composites on nickel foam (NF). CuCo2O4 (CuC) and MnCo2O4 (MnC) nanowires and CuCo2S4 (CuS) and MnCo2S4 (MnS) nanosheets grow vertically on NF as the core by hydrothermal and calcination methods and a PPy film covered on the surface of MCo2O4@MCo2S4 (M = Cu, Mn) as the shell via a chemical bath method to form 3D self-supporting nanoflower-like composite materials. The as-prepared MC@MS@PPy-16/NF (M = Cu, Mn) electrode materials are characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Due to the particularity of the electrode material structure, the MC@MS@PPy-16 (M = Cu, Mn) electrode has a high specific capacitance (Cs, 413.63 mA h g−1 and 654.64 mA h g−1 at 1 A g−1) and the Cs retention rate exceeds 90% after 10 000 cycles. The asymmetric supercapacitor (ASC) device assembled with the MC@MS@PPy-16 (M = Cu, Mn) electrode as the positive electrode, active carbon (AC) as the negative electrode and 6 M KOH as the electrolyte can work stably in a broad voltage range of 0–1.6 V. MC@MS@PPy-16//AC ASC (M = Cu, Mn) devices display excellent electrical characteristics in terms of high energy density (41.34 and 38.75 W h kg−1 at 8000 W kg−1) and cycling stability (Cs retention rates of 84.74% and 80.4% and coulombic efficiencies of 80.15% and 83.69%). These results show that MCo2O4@MCo2S4@polypyrrole composite materials have great application potential in high-performance supercapacitors. [ABSTRACT FROM AUTHOR]

Ti3C2Tx MXene thin-film electrodes are promising for flexible and wearable energy storage devices. Meanwhile, the restacking of MXene nanosheets largely affects their electrochemical properties when processing them into freestanding films. Introducing interlayer spacers can effectively eliminate this restacking problem; however balancing the restacking and mechanical strength of these films remains challenging. Here, an efficient strategy that utilizes ice crystals to help intercalate aniline monomers into a pre-frozen hydro-MXene film, followed by an in situ polymerization, is proposed. The ice crystals grown within the hydro-film significantly enlarge the interlayer space, facilitating the intercalation of aniline monomers dispersed into the MXene film. By minimizing the polyaniline (PANI) loading (0.6 wt%), the resultant PANI/MXene film shows both high mechanical strength (∼47 MPa) and electrochemical performances including a high volumetric capacitance of 1360 F cm−3 (gravimetric capacitance of 385 F g−1), rate performance (53.5% even at an ultrahigh scan rate of 10 V s−1) and stable cycling stability with 96.4% capacitance retention after 10 000 cycles. Moreover, the assembled supercapacitor device demonstrates good structural stability and flexibility under different bending tests. Thus, this work provides an efficient approach for fabricating MXene based thin films with a good balance of mechanical strength and electrochemical performances. [ABSTRACT FROM AUTHOR]

We prepared a composite of aminooxy bifunctional molecules with graphene, which can decompose 91 mg of HCHO by 1 g of bifunctional molecules at room temperature with the only byproduct of water. Moreover, the composite can be regenerated under acidic conditions and 83.5% capacity is retained after 10 cycles. [ABSTRACT FROM AUTHOR]

Activating the redox chemistry of transition metal catalysts to dynamically construct adaptive heterojunctions while incorporating lattice mismatch-induced interfacial stress/lattice strain is critical for designing electrocatalysts with high water oxidation activity. Here, we perform electrochemically induced surface reconstruction of an adaptive hydrangea-like heterojunction (NS/NOOH), where crystalline NiOOH is epitaxially grown on the surface of NiSe nanorods (NS) to induce lattice mismatch and then generate interfacial stress. This lattice strain combined with the sufficient exposure of electrochemically active sites gifted by the hydrangea-like structure and the synergistic interfacial effect between the phases endows NS/NOOH-30 with a 25-fold and 30-fold improvement in OER performance compared with the NS/NOOH counterpart without stress during the initial cycle and original NS, respectively. Only 260 mV of overpotential is required even at high current densities (j = 500 mA cm−2), which meets the industrial requirements. This work demonstrates the importance of in situ surface phase transitions of electrocatalysts to generate interfacial stress and provide new insight into lattice engineering. These new insights also open up the possibility of developing highly active heterojunction catalysts through selected surface reconstruction processes. [ABSTRACT FROM AUTHOR]

Designing high-performance, low-cost non-precious metal bifunctional electrocatalysts for either the hydrogen evolution reaction (HER) or the oxygen evolution reaction (OER) is the key to achieving large-scale hydrogen production from water. Here, we design a porous nanosheet array catalyst of spherical Co3S4 and Ni–Fe sulfide nanosheets grown vertically on FeNi3 foam (NiFeCoSx@FeNi3) with excellent catalytic activity and stability in alkaline solutions. In 1.0 M KOH solution, the current densities of the HER and OER can reach 10 mA cm−2 with minimum overpotentials of 88 mV and 210 mV, respectively. In 1.0 M KOH and 0.33 M urea solutions, NiFeCoSx@FeNi3 needs only 1.42 V to provide a current density of 10 mA cm−2 for the urea oxidation reaction (UOR). The significantly improved catalytic activity should be attributed to the synergistic interaction among the three elements of Ni, Fe and Co as well as the hierarchical porous nanosheet array structure. This work demonstrates that a novel and efficient bifunctional trimetallic catalyst can be rationally designed by controlling the composition and ratio of the elements and the structure. [ABSTRACT FROM AUTHOR]

Layered double hydroxides (LDHs) are widely used as cathode materials for supercapacitors (SCs), thanks to their many advantages. However, the single metal species with limited active sites limit the further improvement of the electrochemical performance of LDH materials. We successfully in situ embedded cobalt sulfide quantum dots (Co9S8-QDs) between the layers of ternary metal LDHs derived from metal–organic-frameworks (MOFs) by selective vulcanization of Co. The prepared Ni3Mn1Co@Co9S8-QDs/NF nanocomposites retain the advantages of LDH materials, such as lower charge transfer resistance. At the same time, the selectively generated ultra-small sized Co9S8-QDs reveal more active sites, which complies with the size minimization strategy, leading to the largely enhanced electrochemical properties. Due to the cooperative effect of LDHs and Co9S8-QDs, the prepared electrode has an excellent capacity (492.1 mA h g−1 at 1 A g−1), remarkable equivalent series resistance (0.499 Ω) and superior capacity retention (90.4% after 10 000 charge–discharge cycles). In addition, the carbon coated Fe2O3 nanoarray is prepared on carbon cloth (CC) as the cathode electrode (Fe2O3@C/CC), and the prepared Ni3Mn1Co@Co9S8-QDs/NF//Fe2O3@C/CC all solid-state asymmetric supercapacitor (ASC) shows an outstanding energy density (71.48 W h kg−1) when the power density is 750 W kg−1 and excellent capacity retention (93.7% after 10 000 charge–discharge cycles). As a result, the construction of composite electrodes with polymetallic LDHs and in situ embedded quantum dots should envision broad prospects. [ABSTRACT FROM AUTHOR]

Flexible wearable sensors have received considerable popularity due to their potential application in monitoring human activities and health conditions. However, traditional pressure sensors always rely on a single mechanism (such as piezoelectric or piezoresistive effect), which shows great limitation in the cooperative monitoring of static and highly dynamic pressure detection and severely restricts their further practical applications. Herein, a new strategy of combining piezoelectric and piezoresistive mechanisms in one single flexible sensor is reported for the realization of dual function detection. In detail, a piezoelectric unit (non-array and array) based on a flexible poly(vinylidene fluoride) (PVDF) polymer is deployed for highly dynamic detection, while the composite of graphite sheet (GS)-decorated PVDF electrospun mat composite serves as a piezoresistive unit for static detection. The device exhibits excellent piezoresistive durability (over 600 cycles) and higher piezoelectric sensitivity of 0.5 N V−1 at the applied frequency of 5 Hz due to the fact that the introduction of a soft piezoresistive layer increases the transverse strain on the piezoelectric layer originating from large deformation of the low stiffness surface. On the basis of the collaborative and complementary advantages, accurate and reliable detection of human motions such as elbow and heel activities are realized, indicating great potential in wearable electronics applications from zero to high frequency. This study provides general guidance for the development of flexible pressure sensors that require dynamic and static cooperative detection capabilities. [ABSTRACT FROM AUTHOR]

Environmentally harmful and high-priced initiators such as azodiisobutyronitrile, perchloric acid and butyllithium are usually essential for most of the polymerization technologies such as radical, cationic and anionic polymerizations. Besides, it is also troublesome to achieve complete separation of initiators from the obtained polymers. Herein, a recyclable catalytic system for the generation of hydroxyl radicals by catalyzing hydrogen peroxide based on bi-nano-bionic enzymes (refers to the bionic enzymes constructed from two kinds of enzymes, Fe3O4@Au NPs) was successfully constructed. The magnetic and flower-like Fe3O4 NPs provided a recyclable and well-dispersed scaffold for immobilization of Au NPs, leading to enhanced catalytic activity of Au bionic enzymes. The designed catalytic system showed excellent catalytic activity for hydroxyl radical generation under various working conditions (pH 7–11, 15–100 °C). Impressively, the catalytic system was then employed as a novel initiating system (Fe3O4@Au NPs/H2O2) for reversible addition–fragmentation chain transfer (RAFT) polymerization of a wide range of functional monomers using different RAFT agents in both aqueous and organic solvents. The established initiating system provided an effective method for RAFT polymerization with a real-time control feature in a recyclable way by magnetic separation. It was found that over 93.9% catalytic activity of Fe3O4@Au was still retained after 4 consecutive operations of RAFT polymerization. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

An effective strategy for regioselective modification and directional assembly of anisotropic nanoparticles is demonstrated to explore the electric field enhancement in assembled gold nanobipyramids compared with gold nanorods. The well-defined secondary plasmonic hot spots between the coupled gold nanobipyramids exhibit the capability for single molecule detection. [ABSTRACT FROM AUTHOR]

Metal–organic frameworks (MOFs) have attracted increasing attention due to their high specific area and abundant redox sites for application in energy storage devices. However, the non-ideal capacity, poor mechanical/chemical stability, random arrangement and low conductivity of most MOFs largely thwart their extensive applications. Hence, designing an easily operated and highly efficient strategy to address these issues has realistic meanings. Herein, a vertically oriented Cu(OH)2 nanorod array was selected as both the template and precursor to synthesize highly oriented star anise-like Co-doped Cu-MOF/Cu2+1O (Cu2+1O refers to the Cu2O with metal excess defects) nanohybrid materials, where the MOF structure is formed through an in situ reverse transformation process. Due to the high conductivity resulting from the presence of “excess copper” and doped cobalt ions, as well as the intimate connection between the Cu-MOF and Cu2+1O, the optimized (0.1Co/Cu-MOF/Cu2+1O) electrode delivers a high areal capacity of 1.548 F cm−2 (518.58 F g−1) and remarkable cycling stability (97.26% after 5000 cycles). Meanwhile, the assembled 0.1Co/Cu-MOF/Cu2+1O//activated carbon hybrid supercapacitor shows an outstanding energy density up to 25.67 W h kg−1 at a power density of 740.44 W kg−1. Therefore, the proposed strategy may open a new avenue to unlock the inherent advantages of MOFs for application in the electrochemical energy storage field. [ABSTRACT FROM AUTHOR]

Amorphous transition-metal (hydr)oxides have proven to be the most promising oxygen evolution reaction (OER) electrocatalysts. Here, a facile and novel strategy for the generation of porous amorphous cobalt oxide through one-step treatment of the cobalt carbonate hydroxide precursor with concentrated sulfuric acid has been reported. Benefiting from the optimized amorphous structure, the prepared catalyst exhibits an excellent water-oxidation activity in an alkaline electrolyte with the demand of 50 mV less overpotential at 10 mA cm−2 compared to that of highly-crystallized Co3O4. Compared with the 400 °C annealing process for Co3O4, the ultrafast acid treatment process within 10 seconds at room-temperature for achieving such amorphous cobalt oxide demonstrates tremendous convenience. More impressively, after continuous testing for 60 h at an overpotential of 370 mV, it still maintains a porous configuration as well as ∼92% of the original current density. Our findings not only present a high-efficiency OER electrocatalyst, but also provide a methodology with broad applicability toward the systematic study of other non-crystal oxides for green energy applications. [ABSTRACT FROM AUTHOR]

The design and development of highly efficient and durable non-precious metal catalysts are of great significance for the HER and the OER, especially bifunctional catalysts for overall water splitting. Here, a series of novel composites of 3D nitrogen-doped graphene foams with homogeneously dispersed CoS1.097 nanoparticles (NPs) are synthesized through hydrazine-induced foaming and thermal-treatment process at different temperatures. Notably, the composite thermally treated at 750 °C (CoS1.097/NGF-750) which possesses continuous 3D porous structures exhibits super-hydrophilic properties and ultra-high catalytic activity, providing a current density of 10 mA cm−2 at a low overpotential of 240 mV for the OER and 124 mV for the HER, respectively. In addition, a self-supported two-electrode electrolyzer assembled using CoS1.097/NGF-750 as both the cathode and anode exhibits the current densities of 10 and 20 mA cm−2 at potentials of 1.56 V and 1.65 V, respectively, and long-term stability (95% of the activity remained after 45 h). Furthermore, this novel catalyst can be produced on a large scale, therefore it could be promising for practical applications in overall water splitting. [ABSTRACT FROM AUTHOR]

Autonomous and self-powered micropumps are in critical demand for versatile cell- and tissue-based applications as well as for low-cost point-of-care testing (POCT) in microfluidics fields. The hydrostatic pressure-driven passive micropumps are simple and widely used, but they cannot maintain steady and continuous flow for long periods of time. Here, we propose a hydrostatic pressure-driven passive micropump enhanced with siphon-based autofill function, which can realize the autonomous and continuous perfusion with well-controlled steady flow over an extended time without electric power consumption. The characterization results reveal that both the cycle number in one refilling loop and the siphon diameter will affect the refilling time. Furthermore, this micropump also enables multiplexed medium delivery under either the same or different flow conditions with high flexibility. The system was validated using an in vitro vasculogenesis model over the course of several days. Most importantly, the device can consistently provide steady medium perfusion for up to 5 days at a predefined hydrostatic pressure drop without the need for supplemental medium changes. We believe that this hydrostatic pressure-driven passive micropump will become a critical module for a broad range of sophisticated microfluidic operations and applications. [ABSTRACT FROM AUTHOR]

The development of flexible electrochemical devices with high-density electrochemical capacitive energy storage and high mechanical strength remains the main obstacle for practical applications. Here, we designed and generated a S/N co-doped graphene based electrode (CoS1.097/GF electrode) with well-distributed CoS1.097 nanoparticles (NPs), which were anchored directly in/on porous carbonized melamine foam by a squeeze-dip-coating and sulfidation process. The CoS1.097/GF electrode shows desired conductivity, cycling stability and high ion-accessible surface area, leading to an ultrahigh specific capacitance of 4476 F g−1 at a current density of 1 A g−1 and a favourable rate capability of 87.1% at 10 A g−1. Furthermore, a high-strength and flexible CoS1.097/GF/KOH/PVA composite film electrode was prepared using KOH/polyvinyl alcohol (KOH/PVA) as a gel electrolyte, and a flexible CoS1.097/GF☋☋GF asymmetric electrochemical capacitor (a-EC) device was produced with a high energy density of 33.2 W h kg−1 at a power density of 374.7 W kg−1, where the KOH/PVA gel works as a solid-state electrolyte and separator. We observed 95.6% capacitance retention after 10 000 cycles within the potential window of 0–1.5 V. Notably, we confirmed that the CoS1.097/GF☋☋GF a-EC device performed at large bending angles (from 0° to 180°), and was able to be twisted into various shapes, indicating its potential for application in wearable and portable electronic devices. [ABSTRACT FROM AUTHOR]

Unique hierarchical cyclic voltammetry oxidation (CVO) Cu@CuO nanorod arrays were obtained by an in situ oxidation reaction with the combination of calcination and cyclic voltammetry oxidation strategies. The areal capacitance of this CVO Cu@CuO electrode reaches 1.674 F cm−2 (594.27 F g−1) at a current density of 2 mA cm−2, which is significantly higher than those of Cu@Cu(OH)2 (0.207 F cm−2) and Cu@CuO (1.307 F cm−2) electrodes. In addition, an excellent rate capacity (1.085 F cm−2 at a current density of 30 mA cm−2) and remarkable cycling stability (96.45% after 4000 cycles) were observed. Additionally, the CVO Cu@CuO nanorod arrays can also be utilized as the positive electrode to manufacture asymmetric supercapacitor (ASC) devices, realizing a high cell voltage of 1.5 V and an outstanding energy density of up to 35.43 W h kg−1 at a power density of 520.99 W kg−1. The excellent electrochemical properties can be credited to the unique hierarchical structures. This work makes it attractive in that the CVO Cu@CuO can be utilized as a potential electrode material for supercapacitors. [ABSTRACT FROM AUTHOR]

Well-controlled, low-toxicity and highly efficient delivery systems for anticancer drugs are a key challenge for the development of a new class of nanocarrier systems for cancer chemotherapy. Graphene oxide (GO) has been developed to be a nanocarrier of anti-cancer drugs due to its large surface area and biocompatibility; however, understanding of the interface chemistry is very limited. In this work, we report efficient loading and controlled release of doxorubicin (DOX) using the tunable surface of GO. A deep understanding of the surface chemistry between GO and DOX is achieved using spectroscopies and atomic force microscopy. Hydrogen bonding and π–π stacking are confirmed to be the non-covalent interactions between the drugs and the carriers. As a result, improvement of DOX delivery from the GO surface can be achieved using vitamin C. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

With the imminent exhaustion of fossil fuels and increasing global energy demands, great effort has been made to design and develop functional materials for exploiting clean renewable energy sources and developing more efficient energy storage systems. Cobalt phosphide is a rapidly rising star on the horizon of highly efficient catalysts with numerous research activities worldwide. In this review, we summarize recent research progress made in cobalt phosphide-based materials as efficient catalysts for hydrogen production and fuel cells, and as electrode materials for batteries. The impacts of phosphorus content on the electrocatalytic activity and other significant structural designs of cobalt phosphides for improving the performance are discussed. Finally, current challenges and future directions for cobalt phosphide-based materials are discussed. [ABSTRACT FROM AUTHOR]

Herein, we develop a spray deposition process for the production of flexible and conductive hollow graphene fibers (HGFs). Firstly, a graphene oxide suspension is spray-coated on silk fibers, which act as a template, followed by the reduction of GO into RGO using HI as the reductant. This simple method gets rid of the picky conditions and complicated process for the fabrication of graphene fibers (GFs) which possess good flexibility, conductivity and a hollow structure. A flexible all-solid hollow graphene fiber supercapacitor (HGFS) is assembled using the as-prepared HGFs and shows an excellent specific capacitance of 76.1 F g−1 (127.4 mF cm−2, 48.5 F cm−3) at a current density of 1 A g−1, excellent rate capability (over 87% retention at 5 A g−1) and high cycling stability with only 9.5% capacitance decay over 2000 recycles at a scan rate of 100 mV s−1. This simple large-scale template method for the preparation of flexible and conductive HGF electrodes could promise broad prospects for high-performance energy storage applications, particularly for next-generation wearable electronic devices. [ABSTRACT FROM AUTHOR]

Herein, we report a new template method for fabricating an arbitrary-shaped compressible nitrogen-doped graphene aerogel (GA). The as-prepared GA remains stable under a maximum compressive strain of 90% or after 50 compression/release cycles at a strain of 80%. The compressible nitrogen-doped GA is used as an electrode to fabricate an all solid-state graphene aerogel supercapacitor (GASC). The as-assembled GASC shows a specific capacitance of 150 F g−1 at a current density of 0.3 A g−1 and a long cycle life with 85.1% capacitance retention after 10 000 cycles at 1 A g−1. In addition, the compressible GASC displays stable electrochemical performance under different compressive strains (0%, 25%, 50% and 75%) or after 100 compression/release cycles under a compressive strain of 50%. The present work highlights the first example of fabricating an arbitrary-shaped compressible GA. Furthermore, the as-obtained GASC overcomes the limitation of previous work which required the assistance of other materials to maintain the mechanical properties. This simple template method for the fabrication of compressible and robust GA electrodes could have enormous potential for high performance compressible energy storage devices. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Carbon quantum dot wrapped gold nanorods were fabricated on an ITO electrode surface via electrostatic interactions. The electron transfer properties of carbon quantum dots on gold nanorod surfaces were systematically investigated by plasmonic resonance scattering spectroscopy. [ABSTRACT FROM AUTHOR]

A novel structure of arrays of Cu/graphene double-nanocaps was developed via a one-step low-temperature chemical vapor deposition (CVD) process. Polystyrene spheres (PSSs) are ingeniously employed as both templates and solid carbon sources. SERS measurements reveal their high sensitivity and stability due to the synergistic effect of Cu and graphene double nanocaps. [ABSTRACT FROM AUTHOR]

The exploration of high-performance and cost-effective water oxidation catalysts operating under mild conditions is still urgent and challenging. In this communication, a nickel-borate nanoarray supported on carbon cloth (Ni-Bi/CC) has been fabricated through oxidative polarization of a nickel oxide nanoarray on CC (NiO/CC) in a borate electrolyte (pH 9.2). As a 3D electrode, this Ni-Bi/CC exhibits superior catalytic activity for water oxidation in 0.1 M potassium borate (K-Bi) solution, yielding a geometrical catalytic current density of 10 mA cm−2 at an overpotential of 470 mV. Notably, this electrode also demonstrates outstanding long-term electrochemical durability for 25 h with 100% Faradaic efficiency. [ABSTRACT FROM AUTHOR]

With the development of wearable electronics, flexible energy devices are now paid more attention, aiming at efficiently converting a variety of physical motion energy of the human body into electricity. This work innovatively proposes a flexible and biocompatible single-friction-surface triboelectric and piezoelectric hybrid generator (TPG) with good transparency. The novel TPG uses Al:ZnO (AZO) as transparent electrodes, P(VDF-TrFE) as the piezoelectric functional layer and PDMS with micro-fabricated pyramids as the triboelectric layer. The proposed TPG can effectively harvest bending and movement energy from human skin under piezoelectric and triboelectric mechanisms. The typical stress–strain curve and transmittance testing of TPG indicates that TPG has outstanding stretchability and transmittance. The generator has an open-circuit output voltage of 25 V under the triboelectric mechanism and a piezoelectric open-circuit output voltage of 2.5 V under the piezoelectric method. The total output voltage and power density of this device are 26 V and 751.1 mW m−2, respectively. In addition, this device would scavenge the mechanical energy from the different parts of the body, such as the human neck, finger, elbow and ankle into electric energy with various signal forms owing to the different contacting moving modes on the friction surface, which will be deployed as a body moving sensor. [ABSTRACT FROM AUTHOR]

To achieve high catalytic activity and stability with low noble-metal loadings on special supports has triggered much research interest in the past few years. Herein, a mild co-reduction strategy was exploited to fabricate glutathione decorated Au clusters (with a size of ∼1.4 nm) on reduced graphene oxide (Au@HSG-rGO) with low Au loadings and high catalytic activity in an aqueous medium. The resultant Au@HSG-rGO complex exhibited 20.8 times higher catalytic activity than Au nanoparticle supported graphene for catalysis of the reduction of 4-nitrophenol (4-NP). The Au@HSG-rGO was packed in a filtering platform to afford a fixed-bed system, with which the catalytic conversion reached 96.03% for 0.2 mM 4-NP solution at a flow rate of 1 mL min−1. In addition, the poly(2-(dimethylamino) ethyl acrylate) modified Au@HSG-rGO (Au@HSG-rGO-PDMAEA) viaπ–π stacking interactions exhibited good recyclability and tunable catalytic activity and only showed slight loss of activity after recycling five times. The PDMAEA served as forest-like shelters to efficiently protect the Au@HSG clusters from aggregation and also endowed the system with enhanced stability and temperature-controlled catalytic activity. Meanwhile, the Au@HSG-rGO showed excellent electrocatalytic activity for the oxygen reduction reaction in alkaline electrolytes. This simple, economical and mild strategy could be generalized to the preparation of other metal cluster complexes for broad catalytic and analytical applications. [ABSTRACT FROM AUTHOR]

Although there are a few research studies on solution-processed p-channel oxide thin-film transistors (TFTs), the strict fabrication conditions and the poor electrical properties have limited their applications in low-power complementary metal oxide semiconductor (CMOS) electronics. Here, the application of the polyol reduction method for processing p-type CuxO and NiOx channel layers and their implementation in TFT devices are reported. The optimized CuxO and NiOx TFTs were achieved at low annealing temperatures (∼300 °C) and exhibited decent electrical properties. Encouraged by the inspiring results obtained on SiO2/Si substrates, the TFT performance was further optimized by device engineering, employing high-k AlOx as the gate dielectric. The fully solution-processed NiOx/AlOx TFT could be operated at a low voltage of 3.5 V and exhibits a high hole mobility of around 25 cm2 V−1 s−1. Our work demonstrates the ability to grow high-quality p-type oxide films and devices via the polyol reduction method over large area substrates while at the same time it provides guidelines for further p-type oxide material and device improvements. [ABSTRACT FROM AUTHOR]

Here, we for the first time synthesized bimetallic Cu/Ag dendrites on graphene paper (Cu/Ag@G) using a facile electrodeposition method to achieve efficient SERS enhancement. Cu/Ag@G combined the electromagnetic enhancement of Cu/Ag dendrites and the chemical enhancement of graphene. SERS was ascribed to the rough metal surface, the synergistic effect of copper and silver nanostructures and the charge transfer between graphene and the molecules. [ABSTRACT FROM AUTHOR]

Here we report self-assembly of ultrathin gold nanowires and single-walled carbon nanotubes with an ultrahigh aspect ratio as a highly sensitive substrate for surface enhanced Raman spectroscopy. And we demonstrated that the hybrids were especially efficient in adsorption of aromatic molecules such as 4-mercaptobenzoic acid and the hybrids materials could be used as a novel platform for trace level detection in the verification of paper notes through the Raman enhancement technique. [ABSTRACT FROM AUTHOR]

Carbon quantum dots (CQDs) are attracting tremendous interest owing to their low toxicity, water dispersibility, biocompatibility, optical properties and wide applicability. Herein, CQDs with an average diameter of (4.0 ± 0.2) nm and high crystallinity were produced simply from the electrochemical oxidation of a graphite electrode in alkaline alcohols. The as-formed CQDs dispersion was colourless but the dispersion gradually changed to bright yellow when stored in ambient conditions. Based on UV-Vis absorption, fluorescence spectroscopy, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and high-resolution transmission electron microscopy (HRTEM), this colour change appeared to be due to oxygenation of surface species over time. Furthermore, the CQDs were used in specific and sensitive detection of ferric ion (Fe3+) with broad linear ranges of 10–200 μM with a low limit of detection of 1.8 μM (S/N = 3). The application of the CQDs for Fe3+ detection in tap water was demonstrated and the possible mechanism was also discussed. Finally, based on their good characteristics of low cytotoxicity and excellent biocompatibility, the CQDs were successfully applied to cell imaging. [ABSTRACT FROM AUTHOR]

In this communication, we report an electrocatalyst for full water splitting based on CoP2 nanoparticles grown on reduced graphene oxide sheets (CoP2/RGO). As a novel non-noble-metal electrocatalyst, CoP2/RGO shows an ultra-high catalytic activity in alkaline electrolyte which only requires a cell voltage of 1.56 V to attain a current density of 10 mA cm−2 for full water splitting. [ABSTRACT FROM AUTHOR]