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The tribocorrosion performance of low-temperature steels is vital for use in hostile environments. This study aims to investigate the tribocorrosion behavior of FH36 low-temperature steel with two distinct microstructures of tempered martensite (TM) and tempered sorbite (TS), respectively. Also, the coefficient of friction, surface morphologies, electrochemical properties, and corrosion features of the two steels were investigated. The results showed that the TM and TS steel exhibited outstanding impact toughness values of 239 and 306 J at −60°C, respectively. The friction coefficient and the electrochemical impedance in the TM steel were lower than those of the TS steel, while the scratch was deeper and narrower in the TM steel. Both the microstructure and the electrochemical corrosion affect the wear resistance of the low-temperature steels during the tribocorrosion process. The friction can accelerate the adsorption of Cl− ions that enrich the pits near the scratches, and the pitting of the TM steel was severe.

Currently, the exploration of wearable strain sensors that can work under subzero temperatures while simultaneously possessing anti-interference capability toward temperature is still a grand challenge. Herein, we present a low-temperature wearable strain sensor that is constructed via the incorporation of a Ag nanowires/graphene (Ag NWs/G) composite into the polydimethylsiloxane (PDMS) polymer. The Ag NWs/G/PDMS strain sensor exhibits promising flexibility at a very low temperature (-40 °C), outstanding fatigue resistance with low hysteresis energy, and near-zero temperature coefficient of resistance (TCR). The Ag NWs/G/PDMS strain sensor shows excellent sensing performance under subzero temperatures with a very high gauge factor of 9156 under a strain of36%, accompanied by a noninterference characteristic to temperature (-40 to 20 °C). The Ag NWs/G/PDMS strain sensor also demonstrates the feasibility of monitoring various human movements such as finger bending, arm waving, wrist rotation, and knee bending under both room temperature and low-temperature conditions. This work initiates a new promising strategy to construct next-generation wearable strain sensors that can work stably and effectively under very low temperatures.

Rechargeable, aqueous Zn-ion batteries in a neutral or mildly acidic electrolyte have attracted great attention. The fabrication of binder-free electrodes to boost the Zn2+ transport is extremely desirable for the development of aqueous zinc-ion batteries but remains a big challenge. Herein, we revealed a spontaneous knitting behaviour in 6.7 nm thin, flexible (NH4)0.38V2O5 nanoribbons by a hydrothermal route to form binder-free paper cathode for aqueous zinc-ion batteries. Conductive multi-walled carbon nanotubes (CNTs) was also successfully imbedded into this paper to enhance the electronic conductivity and produce abundant meshes (pore size: 1-3 µm) inside the paper. Taking advantage of the binder-free design and the porous architecture of the paper cathode, it delivered a reversible capacities of 465 mAh·g−1 at 100 mA·g−1. A capacity retention of above 89.3 % after 500 cycles at 100 mA·g−1 has been achieved. Importantly, the resulting paper electrode exhibited a specific energy as high as 343 Wh·kg−1, which remarkably outperforms most of the zinc-ion batteries based on powder form cathode with the presence of polymer binder. Our work reveals a novel self-grown strategy for the binder-free, freestanding electrodes on Zn2+ ion storage from the ultrathin, flexible ammonium vanadates nanostructures, and it might be applicable to the storage of other metal/non-metallic ions (Na+, Mg2+, Ca2+, Al3+, NH4+ etc.) in next-generation electrochemical energy storage devices.

The exploration of wearable strain sensors with new characteristics and functionalities could fuel the rapid development of Internet of Things (IoT) technology for the healthcare industry. Herein, we present a flexible, waterproof, and highly sensitive strain sensor that is fabricated by integrating graphene (G), carbon black (CB), and polydimethylsiloxane (PDMS) into the three-dimensional (3D) framework of commercial Ni sponge via a simple, cost-effective, and scalable drop-coating method. The G/CB/Ni strain sensor demonstrates good flexibility, high sensitivity (gauge factor of 138 at 16% strain), and long-term stability. The G/CB/Ni sensor could not only precisely monitor subtle human motions such as pulse, blinking, and swallowing, but it also shows potential in testing muscle strength. A wireless sensor system that consists of the G/CB/Ni strain sensor, an STM32 controller, a ZigBee module, and a portable power source is assembled, which enables remote transmission of data collected from the sensor to the computer wirelessly. The G/CB/Ni sensor also exhibits excellent waterproofness and can be safely used to monitor human motions under humid conditions and in water. The G/CB/Ni strain sensor featuring flexibility, high sensitivity, and waterproofness has great potential for applications in healthcare management, personal rehabilitation training, and outdoor motion monitoring.

Modifying the commercial melamine sponge (MS) that intrinsically possesses highly porous open-cell structure with graphene oxide (GO) or GO-based nanocomposites (NCs) is a facile, effective, and low-cost route to fabricate three-dimensional (3D) porous materials with multifunctionality. Herein, we fabricated two types of 3D MSs that were separately functionalized by the reduced GO (RGO) sheets and Ag/RGO NC through combined methods of chemical reduction and immersion process. The simple immersion process brought out the transition of superhydrophilic MS to highly hydrophobic RGO-MS and Ag/RGO-MS. Due to the unique surface topography and high porosity, the RGO-MS exhibited remarkable absorption capacity of 41–91 times its own weight for a wide range of oils and organic solvents. Both the RGO-MS and Ag/RGO-MS showed excellent oil-water separation efficiencies. The Ag/RGO-MS not only exhibited outstanding absorption capacity and recyclability, but also possessed ideal antibacterial performance towards bacteria of Staphylococcus sciuri, Shewanella MR-1, Pseudoalteromonas lipolytica, and Vibrio natriegens. The Ag/RGO-MS featured with hydrophobicity and antibacterial activity is a promising candidate for potential applications in oil-spill disposal and water disinfection. This study provides an effective strategy for designing and fabricating the 3D porous materials with novel functionalities.

The Bacillus subtilis can induce biomineralized film formation on the surface of steel, which is associated with the positive effects on corrosion. However, the addition of 0.4 wt% Cu to the steel changes the film composition and structures significantly. The biological analyses reveal the mechanism through which Cu influences the metabolism of Bacillus subtilis and carbonate precipitation. The latter plays an important role in protecting corrosion. Furthermore, corrosion pits are larger and more for Cu-steel compared with control steel (free of Cu). This study introduces a new insight for designing an anticorrosion steel in the presence of biomineralized film.

The development of miniaturized, low-cost, and high-performance acetone gas sensors is highly desirable for workshop safety management and human health diagnosis. Herein, we present a portable integrated system for real-time detection of acetone concentration based on a novel 2D/2D nanocomposite of tungsten oxide hydrate (WO3·H2O) nanoplates and graphene nanoplatelets (GNPs). The GNP-WO3·H2O nanocomposites were first synthesized using a precipitation process at room temperature with sodium tungstate dihydrate as the precursor and GNP as the template. At low GNP content (0.5 and 1.0 wt %), the GNP-WO3·H2O nanocomposites exhibited superior sensitivities to the pure WO3·H2O nanoplates. The GNP-WO3·H2O nanocomposite with 1.0 wt % GNP addition could deliver a sensitivity of 6.7 toward 5 ppm acetone, with a fast response time of 7 s. After annealing at 200–400 °C, the acetone-sensing performance of both the WO3·H2O nanoplates and GNP-WO3·H2O nanocomposites were obviously deteriorated, which can be attributed to...

In this work, a novel MnO2/g-C3N4@polypyrrole (PPy) ternary nanocomposite (NC) was fabricated by coupling the MnO2 nanorods with the two-dimensional g-C3N4 sheets and the conductive PPy. The MnO2/g-C3N4@PPy NC electrode exhibited a high specific capacitance of 274 F g−1 at a current density of 2 A g−1, which was 1.88 times than that of the MnO2@PPy NC electrode. The MnO2/g-C3N4@PPy NC electrode also possessed outstanding cyclic stability with 95% capacitance retention after 1000 cycles. The present strategy for fabricating ternary nanocomposite uses low-cost raw materials and simple preparation method, which provides an alternative route to optimize the SC performance of other pseudocapacitive oxides.

Flexible strain sensors are attracting more and more attentions in wearable devices and electronic skins. Currently, the fabrication of flexible strain sensor with features of high sensitivity and wide linear working range is still a great challenge. Herein, a stretchable and wearable strain sensor is fabricated with the ZnO nanoparticles (NPs)/graphene nanoplatelets nanocomposite (ZnO/GNP NC) as both the sensing element and reinforcement phase. The ZnO/GNP NC strain sensor exhibits fascinating performance, including high mechanical properties (fracture strength of 0.6 MPa and elongation of ~ 90%), large working range of 0–44%, high sensitivity (gauge factor of 8.8–12.8), and good reproducibility over 1700 cycles. Importantly, the ZnO/GNP NC strain sensor holds perfect linearity (R2 = 0.999) in the whole working range, which can be attributed to the coupling effect between the ZnO NPs and the GNP. The ZnO/GNP NC strain sensor can not only detect large human motions such as elbow rotation, wrist rotation, clenching fist, and waving badminton racket, but also monitor subtle human motions in real time, such as pulse, phonation, coughing, and swallowing. The wide linear working range of the ZnO/GNP NC strain sensor makes it a potential choice for the application of wearable devices.

Molybdenum sulfide (MoS2) has become a promising anode material for sodium-ion batteries (SIBs) due to its unique two-dimensional layered structure and high theoretical capacity. However, the poor electrical conductivity and unceasing volume change of MoS2 electrode during charge/discharge process will result in its poor rate performance and rapid capacity fading. In this work, few-layered MoS2@N-doped carbon network (F-MoS2@NCN) was synthesized through a facile freeze drying and annealing process. The N-doped carbon network could effectively improve the charge transport ability and accommodate the volume change of MoS2, while the few-layered MoS2 structure could also shorten the Na+ diffusion pathway and improves its diffusion mobility during cycling process. Benefiting from the synergetic effects between N-doped carbon network and few-layered MoS2, F-MoS2@NCN could maintain a high reversible capacity of 354.0 mAh g−1 at 50 mA g−1 after 100 cycles and deliver a reversible capacity of 298.7 mAh g−1 at a current density of 1000 mA g−1. This work should provide new insights into MoS2-based anode materials for SIBs.

Steel corrosion is a global problem in marine engineering. Numerous inhibitory treatments have been applied to mitigate the degradation of metallic materials; however, they typically have a high cost and are not environmental friendly. Here, we present a novel and "green" approach for the protection of steel by a marine bacterium Pseudoalteromonas lipolytica. This approach protects steel from corrosion in seawater via the formation of a biofilm followed by the formation of an organic-inorganic hybrid film. The hybrid film is composed of multiple layers of calcite and bacterial extracellular polymeric substances, exhibiting high and stable barrier protection efficiency and further providing an in situ self-healing activity. The process involving the key transition from biofilm to biomineralized film is essential for its lasting anticorrosion activity, which overcomes the instability of biofilm protection on corrosion. Therefore, this study introduces a new perspective and an option for anticorrosion control in marine environments.

The ever-dwindling freshwater sources and ever-increasing need for freshwater resources are regarded as two important concerns for current society. Solar vapor generation has proven to be an effective and reliable solar-driven technology to overcome these concerns. However, it is a big challenge to prepare low-cost and high-efficiency solar absorber for solar vapor generation. Herein, we report a novel structurally integrated solar absorber composed of CuS nanoflowers and semipermeable collodion membrane (SCM). Three-dimensional (3D) covellite CuS nanoflowers composed of nanosheets have been synthesized with a facile hydrothermal route and their morphology and structure are investigated with various analytical techniques. High solar vapor generation efficiencies of 68.6% and 81.2% were achieved with CuS/SCM under 1 and 4 sun irradiation, respectively, much higher than that of the CuS nanofluid. A stable solar vapor generation performance has been demonstrated over 20 cycles. These results display a promising potential of CuS/SCM as a solar-absorber for efficient solar vapor generation.

Water evaporation, a promising and environmentally friendly technology driven by local hot spots on the water-air interface, is an efficient way to utilize solar energy. Herein, we present a novel laminar solar absorber consisting of graphite powder (GP) and a semipermeable collodion membrane (SCM) as an integrated structural system for highly efficient water evaporation. The GP/SCM composite can efficiently convert the absorbed solar energy to heat energy, e.g., the 8 mg-GP/SCM (i.e., the GP/SCM with 8 mg GP added) enables water evaporation with high efficiency of 56.8% under 1.5 kW/m2 irradiation and 65.8% under 3 kW/m2 irradiation, respectively. Cycling tests verify that the GP/SCM could retain stable water evaporation performance over 20 cycles under the same conditions. Contrast experiments show that the other carbon-containing solar-absorbers, such as acetylene black (AB) and graphene nanoplates (GNPs) in SCM, display relatively low evaporation efficiency of 41.4% and 36.7%, respectively, under the simulated solar irradiation with a light density of 1.5 kW/m2. The laminar GP/SCM composite obtained in our work is low-cost, easy-to-prepare, recyclable, and highly efficient in its photothermal performance, so that it distinctly contributes to water evaporation.

Electrochromic (EC) energy storage devices that could realize the multifunctional integration of energy storage and electrochromism have gained much recent attention. Herein, an EC battery based on the hybrid film of W18O49 and polyaniline (PANI) is developed and assembled, which integrates energy storage and EC functions in one device. The W18O49/PANI-EC battery delivers a discharging capacity of 52.96 mA h g−1, which is about two times higher than that of the W18O49-EC battery. Sunlight irradiation could greatly promote the oxidation reactions of both W18O49 and PANI during the charging process of the W18O49/PANI-EC battery, thus effectively accelerating the charging rate. This work provides a green, convenient, environmentally friendly, and cost-free charging strategy for the EC energy systems and could further advance the development of the multifunctional EC devices based on the organic/inorganic composites.

A heterogeneous nanocomposite (NC) of g-C 3 N 4 /W 18 O 49 based on the coupling of W 18 O 49 nanorods (NRs) with the graphitic carbon nitride (g-C 3 N 4 ) sheets has been synthesised via a solvothermal method. The as-synthesised products were characterised by X-ray diffraction, X-ray photoelectron spectrometry, and transmission electron microscopy. The g-C 3 N 4 /W 18 O 49 NC exhibited very strong adsorption ability towards the methylene blue (MB) dye and demonstrated a high removal efficiency of 99.14% after 0.5 h equilibration in dark. Compared to the g-C 3 N 4 sheets and W 18 O 49 NRs, the g-C 3 N 4 /W 18 O 49 NC exhibited higher removal efficiencies towards both the MB and methyl orange (MO) dyes via a combination of adsorption and degradation. The photocatalytic process of the g-C 3 N 4 /W 18 O 49 NC followed the Z-scheme photocatalytic mechanism. This work provides an efficient strategy for the synthesis of g-C 3 N 4 -based heterogeneous photocatalysts.

The development of flexible electronics has an important impact on areas ranging from stretchable sensors and bendable batteries to wearable devices. Here, a facile, effective, low-cost, and convenient strategy has been employed to fabricate flexible strain sensor with hexagonal ZnO nanorods (NRs) and carbon black as sensing elements, polydimethylsiloxane (PDMS) as matrix, and latex film as substrate. The as-assembled strain sensors hold the merits of high flexibility, high sensitivity, large workable strain range, good linearity, and ideal stability. Compared to the carbon black-based sensor, the ZnO/carbon black-based sensor exhibits highly enhanced sensitivity under tensile stress. The ZnO/carbon black-based sensor also demonstrates the capability of detecting and differentiating various degrees of human motions such as wrist rotation, knee flexion, and finger tapping, as well as the competence of monitoring human activity like pulse beat. The present method for the assembly of the ZnO-based flexible strain sensor opens up a new route for the fabrication of other wearable flexible electronics.

The increasing energy and environmental concerns have spurred enormous research interest towards developing various renewable energy and sustainable environmental solutions. Photothermal conversion for interfacial solar vapor generation is a promising, green energy technology and efficient route for desalination and purification of seawater, i.e. for those parts where freshwater shortage is a severe concern and clean energy is not available. Eco-friendly, highly efficient and low-cost interfacial evaporators are highly desirable for the practical and widespread application of this technology. In this work, we have demonstrated a novel interfacial evaporator employing Cu9S5 nanonets with heterogeneous hexagonal holes as the photothermal conversion material and a microporous poly(vinylidene fluoride) membrane (PVDFM) as the supporting material. The Cu9S5/PVDFM evaporator displays a broadband (from 250 to 2000 nm) and large (∼91.7%) solar absorptance. The porous structures of Cu9S5 nanonets and PVDFM facilitate the water transportation, and the large optical absorption of Cu9S5/PVDFM converts most of the solar energy to thermal energy, producing water vapor with high efficiency. The Cu9S5/PVDFM evaporator exhibits solar vapor generation efficiencies of 80.2 ± 0.6% and 91.5 ± 1.1% under one-sun and four-sun irradiation, respectively, making it among the best copper sulphide-based solar evaporators reported so far. This Cu9S5/PVDFM evaporator is reusable, flexible, highly efficient, easy to prepare, easy to scale up, and controllable for tailoring, showing a promising future for interfacial solar vapor generation.

The development of metal oxide semiconductors-based gas sensors that can simultaneously achieve high response and low detection limit towards formaldehyde (HCHO) remains a great challenge so far. In this work, we present the formation of porous SnO2 nanosheets via direct calcination of a Sn-based metal-organic framework that was prepared via a facile wet chemistry method with deionized water as solvent at 80 °C. The porous SnO2 nanosheets are found to be constructed by the interconnection of ultrafine nanoparticles with sizes of 4–9 nm, which is comparable to the Debye length of SnO2. The gas sensor based on the porous SnO2 nanosheets demonstrate a broad detection range towards HCHO (0.05–500 ppm), a low operating temperature (140 °C), very high response (540.8 to 50 ppm HCHO), extremely low detection limit (0.31 ppb), ideal selectivity, and outstanding reproducibility and durability. The excellent HCHO-sensing performance of the SnO2 sensor could be attributed to the high specific surface area (125.92 m2/g) of the porous SnO2 nanosheets, the ultrafine sizes of the SnO2 nanoparticles, and the presence of abundant of mesopores within the nanosheets. The porous SnO2 nanosheets with excellent HCHO-sensing characteristics may find widespread applications in fabricating gas sensors for detecting ppb-level HCHO.

Metal oxide semiconductor (MOS) gas sensors are promising for applications in environmental monitoring, dangerous gas detection, and disease diagnosis. Seeking for advanced MOS sensing materials that possess high sensitivity and low limit of detection (LOD) at sub-ppm level is a great challenge. Here, we report the first creation of two-dimensional (2D) WO3 nanosheets by annealing of the inorganic fullerene (IF)-like WS2 nanoparticles that were prepared via sulfurization of WO3 nanoparticles. Transformation of WS2 to WO3 was realised during the annealing process, simultaneously accompanied by the collapse of the hollow IF-WS2 structures and the formation of tiny 2D WO3 nanosheets with a lateral size of 40−80 nm. The resulting 2D WO3 nanosheets exhibited highly enhanced acetone-sensing performance in terms of sensitivity, selectivity, and response/recovery rates compared with the WO3 nanoparticles used as precursor for the synthesis of the IF-WS2 nanoparticles. The nanosheets also demonstrated great repeatability, reliable long-term stability, and very low LOD, making them a promising candidate as gas sensor to detect breath acetone.

Rare-earth-doped WO 2.72 microspheres (RE-WO 2.72 MSs) have been successfully synthesized by using a facile solvothermal route with tungsten salt as precursor, RE (RE=Ce, La, and Y) metal salts as dopants, and ethanol as solvent. Results of X-ray diffraction (XRD), X-ray photoelectron spectrometry (XPS), and energy dispersive spectroscopy (EDS) showed that the solvothermal process allowed for the homogeneous doping of WO 2.72 while maintaining the original crystal structure. The RE doping could effectively engineer the bandgap of WO 2.72 , which could not only enhance the light-harvesting ability but also deduce up-shift of both the conduction band and valence band. Compared to the undoped WO 2.72 nanorods (NRs), the RE-WO 2.72 MSs exhibited highly enhanced photocatalytic properties for the degradation of methylene blue (MB) under full spectrum light irradiation. This work provides a versatile strategy for the synthesis of RE-doped tungsten oxides and can be extended to the doping of other oxide semiconductors.

A detailed transformation process of cation exchange (CE) chemistry from hexagonal phase CdS to CdS-Cu7S4 core-shell heterostructures nanorods and eventually to monoclinic phase Cu7S4 nanorods is reported. Applications of the nanorods in environmental pollution removal, photothermal conversion and light-induced water evaporation were investigated. The influence of the reaction time, morphology, and crystal phase on the photocatalysis, photothermal conversion and light-induced water evaporation was discussed. The results showed maximum removal value of rhodamine B by 97.8% at 1 h timepoint. Aqueous dispersion of the core-shell CdS-Cu7S4 heterostructures nanorods prepared with 2 h (1.0 g/L) exhibited a good photothermal conversion performance as it saw increase in sample temperature by 37.8 oC in 300 s under the irradiation of 980 nm laser. The exposure of as-obtained sample film to simulated sunlight irradiation at 2 h (8 mg) increased the weight loss of pure water by 0.62 g in 30 min with the water evaporation efficiency up to 48.4%. We are reporting an excellent light-induced water evaporation performance potential of the nanorods discussed.

WO3·H2O nanoflakes were successfully synthesized by using a facile, effective, and green sonochemical route with distilled water as solvent. The as-synthesized WO3·H2O nanoflakes have been characterized by X-ray diffraction, X-ray spectroscopy, Raman spectroscopy, and scanning electron microscopy. The WO3·H2O nanoflakes deposited onto different substrates have been found to exhibit highly stable electrochromic (EC) performance with high color contrast and fast response time. A flexible electrochromic device (ECD) based on the WO3·H2O nanoflakes have been assembled with polyethylene terephthalate coated with ITO (ITO-PET) as substrate. The ideal electrochromic activities in combination with flexibility make the WO3·H2O nanoflakes-based ECDs promising candidate in flexible electronics.

The corrosion behavior of zinc-rich epoxy primers or paints (ZRPs) with different conducting polyaniline-grafted graphene (PANI/Gr) contents was investigated. Conductivity of the formed PANI/Gr nanosheets was significantly improved by employing the Gr as the inner template to synthesize the PANI. The protective properties and electrochemical behavior of coatings with artificial defects were investigated by monitoring the free corrosion potential versus time and by using localized electrochemical impedance spectroscopy (LEIS). A synergetic enhancement of the physical barrier role of the coating and the zinc sacrificial cathodic protection was achieved in the case of ZRP including PANI/Gr nanosheets. In addition, the ZRP mixed with the PANI/Gr at a content of 0.6% exhibited the best anticorrosion performance across the range of investigated PANI/Gr contents.

The marine bacterium, Vibrio natriegens, grows quickly in a marine environment and can significantly accelerate the corrosion of steel materials. Here, we present an approach to inhibit V. natriegens-induced corrosion by biomineralization. The corrosion of steel is mitigated in seawater via the formation of a biomineralized film induced by Bacillus subtilis. The film is composed of extracellular polymeric substances (EPS) and calcite, exhibiting stable anti-corrosion activity. The microbial diversity and medium chemistry tests demonstrated that the inhibition of V. natriegens growth by B. subtilis was essential for the formation of the biomineralized film.

Creating an environmentally friendly and energy-efficient strategy to fabricate oil-water separation materials for dealing with oil spill remains a great challenge. Herein, we presented a superhydrophobic calcium carbonate (CaCO3) coated-stainless steel mesh (SSM) fabricated using a bacterially induced biomineralization technique and subsequent surface modification with stearic acid (SA). In the presence of Bacillus subtilis, a commonly existing bacterium in soil and sea, a continuous, dense, and thick CaCO3 coating could be formed on the SSM surface based on the biomineralization effect, forming the superhydrophilic mesh (CaCO3-SSM). The superhydrophilic CaCO3-SSM was then modified by stearic acid (SA) to obtain the superhydrophobic mesh (SA/CaCO3-SSM). The SA/CaCO3-SSM showed high oil fluxes (0.2-9.12×104 L·m-2·h-1) and high separation efficiencies (>94.8%) for various oil/water mixtures. Furthermore, the SA/CaCO3-SSM demonstrated ideal wear resistance, outstanding anti-pollution performance, and promising anti-icing characteristic, endowing it with the capability to work under harsh environments. This study provides an inexpensive, environmental-friendly, and pollution-free method to construct superhydrophilic or superhydrophobic surfaces and opens a new avenue for the fabrication of oil-water separation meshes with multifunctionality.

We demonstrate an in situ grown method to fabricate ZnMn2O4 3D hierarchical architecture. The mesoporous micro-polyhedrons are self-supported by naturally grown arms to build an integrated 3D architecture on Au electrode. The synthesis mechanism is schematically illustrated. Employing the ZnMn2O4 3D hierarchical architecture as enzyme loading matrix can provide high active sites, favorable enzymes immobilization, second catalysis, integrated transporting channels and high stability. The enhanced biosensing performance to glucose was achieved by immobilizing GOx into this hierarchical architecture. This in situ grown strategy can avoid the damage caused by mixture, stack, squash and adhesion in fabricating the working electrode.

A novel hybrid nanocomposite composed of AgCl nanoparticles and W 18 O 49 nanorods was fabricated through a facile, clean, efficient deposition route. The AgCl–W 18 O 49 nanocomposite has been found to exhibit excellent antibacterial activity, which may arise from the high-density loading of the AgCl nanoparticles on the W 18 O 49 nanorods and the strongly-coupled interaction between the two components. Under light irradiation, partially photoreduction of the AgCl nanoparticles could convert the AgCl–W 18 O 49 nanocomposite to the plasmonic Ag–AgCl–W 18 O 49 nanophotocatalyst with enhanced antibacterial activity. The AgCl–W 18 O 49 nanocomposite is promising candidate for potential application in the field of marine antifouling coatings.

In this work, we successfully synthesized the silver-reduced graphene oxide (Ag-rGO) composites based on the in situ growth of Ag nanoparticles (NPs) on the surfaces of the GO sheets through a one-pot solvothermal method without using any surfactants or modifiers. The as-synthesized Ag-rGO composites have been characterized by X-ray diffraction, X-ray photoelectron spectrometry and electron microscopy. Results showed that high-density Ag NPs and dots with uniform size distribution were grown on the surfaces of the GO sheets, accompanied by the reduction of GO to rGO. By simply changing the concentration of Ag + ions in the solvothermal reaction system, the size and distribution of the Ag nanocrystals could be controlled. The antibacterial properties of the Ag-rGO composites were investigated by combined techniques of inhibition zone method, plate colony-counting method and bacterial growth curve. The Ag-rGO composites have been found to exhibit excellent antibacterial properties with long-term effects, which could effectively inhibit the growth of bacteria of Vibrio natriegens and Bacillus sp. 1NLA3E . The strongly-coupled interaction between the Ag nanocrystals and the rGO supports as well as the presence of the Ag dots contributed equally to the prominent long-term antibacterial performance of the Ag-rGO composites. The present Ag-rGO composites may find important environmental applications.

A series of ZnO-based heterogeneous photocatalysts, including Ag-ZnO, ZnO- and Ag-ZnO-reduced graphene oxide (rGO) nanocomposites, was successfully synthesized by a one-pot solvothermal route. The as-synthesized products were systematically characterized using combined techniques of X-ray diffraction, X-ray photoelectron spectrometry, electron microscopy, and energy dispersive spectrometry. The resulting ZnO-based photocatalysts exhibited selective photocatalytic behavior towards the degradation of different organic dyes under solar light irradiation. Compared with plain ZnO nanoparticles, the heterogeneous nanocomposite photocatalysts of Ag-ZnO, ZnO- and Ag-ZnO-rGO showed significantly improved photocatalytic activities. The Ag-ZnO nanocomposite exhibited the highest photocatalytic efficiency, which can be ascribed to its core-shell structure with strong interfacial coupling between the Ag shell and the ZnO core as well as the surface plasmon resonance effect of the Ag. The ZnO- and Ag-ZnO-rGO nanocomposites displayed excellent recyclability, due to the strongly coupled interactions between the ZnO or Ag nanoparticles and the rGO support. The ZnO-rGO nanocomposite is the most promising candidate for photocatalysis application with excellent comprehensive performance. This study will not only provide guidance for the selection of ZnO-based heterogeneous photocatalysts, but also open new opportunities for the synthesis of other heterogeneous photocatalysts. Keywords: ZnO, Photocatalyst, Heterogeneous, Solvothermal, Reduced graphene oxide

Electrochromic (EC) energy storage devices that possess characteristics of energy storage and electrochromism are highly desirable and have increasingly attracted research interests, whilst devices that can be stretched or are flexible have received very little attention. Herein, we report a flexible and rechargeable aluminium (Al) ion EC battery (ECB), which consists of a WO3 film as positive electrode, PET/ITO as substrate, Al sheet as negative electrode, aluminum trichloride (AlCl3) aqueous solution as electrolyte, and absorptive glass mat (AGM) as electrolyte carrier and separator. The ECB exhibits a high specific capacity of 142 mAhg−1, while demonstrating reversible color transitions between white (bleached state) and dark blue (colored state) during the cyclic charge/discharge processes. Furthermore, the ECB can work at bending angles of 0-80° with a capacity retention of 92.3% after 40 bending cycles. The flexibility of the ECB is ascribed to the flexible, porous, and highly stable features of the AGM as well as the deformability of the PET/ITO substrate. The potential widow of the ECB can be largely enhanced by connecting small-sized ECBs internally in series while maintaining the energy density unchanged. The present study demonstrates that the ECB using the AGM as the electrolyte carrier and separator may have great potentials for the construction of both flexible, portable electronics and smart windows.

The development of gas sensor that is capable of detecting ppb-level detection of acetone and possesses high response toward low-concentration acetone remains a great challenge. Herein, we present the construction of the W18O49/Ti3C2Tx composites based on the in situ grown of the 1D W18O49 nanorods (NRs) on the surfaces of the 2D Ti3C2Tx Mxene sheets via a facile solvothermal process. The W18O49/Ti3C2Tx composites exhibit high response to low concentration acetone (11.6 to 20 ppm acetone), ideal selectivity, long-term stability, very low limit of detection of 170 ppb acetone, and fast response and recover rates (5.6/6 s to 170 ppb acetone). Compared to the W18O49 NRs and Ti3C2Tx sheets, the W18O49/Ti3C2Tx composites show significant improvement on the acetone-sensing performance, which can be ascribed to the homogeneous distribution of the W18O49 NRs on the Ti3C2Tx surface, the removal of the fluorine-containing groups from the Ti3C2Tx after the solvothermal process, and the synergistic interfacial interactions between the W18O49 NRs and the Ti3C2Tx sheets. The synthesis of the 1D/2D W18O49/Ti3C2Tx Mxene composites provides a new avenue to develop other promising hybrids for acetone sensing.

Polyaniline/cerium dioxide (PANI/CeO2) nanocomposite (NPs) was synthesized by in situ polymerization of aniline in the presence of CeO2 NPs. Various analytical facilities, i.e., powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HRTEM), were utilized to characterize the synthesized CeO2 and PANI/CeO2 NPs. The coatings prepared from the synthesized PANI/CeO2 NPs exhibited excellent corrosion resistance that was superior to epoxy coatings added with PANI in NaCl solution. The exceptional improvement of corrosion protection performance of the PANI/CeO2 /epoxy coatings is associated with the synergetic protection of the enhancement of the protective barrier due to the role of CeO2 NPs and PANI against the diffusion of aggressive ions (e.g., Cl−) and the improvement of self-healing protection attributed to the redox behavior of PANI. Thus, the hybrid PANI/CeO2 NPs are considered as the best route to enhance the protection performance of the epoxy coatings on carbon steel.

Solar vapor generation has attracted tremendous attention as one of the most efficient ways of utilizing solar energy. It is highly desirable to develop low-cost, eco-friendly, and high-efficiency solar absorbers for practical applications of solar vapor generation. Herein, a three-dimensional plasmonic covellite CuS hierarchical nanostructure has been synthesized as the light-absorbing material via a facile one-pot hydrothermal method for structurally integrated solar absorbers with microporous poly(vinylidene fluoride) membrane (PVDFM) as the supporting material. A broadband and highly efficient light absorption has been achieved in the wavelength of 300-2500 nm, along with high water evaporation efficiencies of 90.4 ± 1.1 and 93.3 ± 2.0% under 1 and 4 sun irradiation, respectively. Meanwhile, stable performance has been demonstrated for over 20 consecutive runs without much performance degradation. To the best of our knowledge, this is the highest performance among the copper sulfide-based solar absorbers. With the additional features of low-cost and convenient fabrication, this plasmonic solar absorber exhibits a tremendous potential for practical solar vapor generation.

The effect of single-layer graphene sheets (Gr) on the corrosion protection of zinc-rich epoxy primers (ZRPs) was investigated. Scanning electron microscopy (SEM) with an energy dispersive spectrometer (EDS) were used to characterize morphology and composition of the coatings after immersion for 25 days. The cross-sectional SEM images and X-ray photoelectron spectroscopy (XPS) confirmed that the addition of single-layer graphene facilitated assembling of zinc oxides on the interface between the coating and the steel. The open circuit potential (OCP), electrochemical impedance spectroscopy (EIS) measurements revealed that both the cathodic protection and barrier performance of the ZRP were enhanced after addition of 0.6 wt. % Gr (Gr0.6-ZRP). In addition, the cathodic protection property of the Gr0.6-ZRP was characterized quantitatively by localized electrochemical impedance spectroscopy (LEIS) in the presence of an artificial scratch on the coating. The results demonstrate that moderate amounts of single-layer graphene can significantly improve corrosion resistance of ZRP, due to the barrier protection and cathodic protection effects.

Well-exfoliated graphene oxide sheets were initially fabricated through a modified pressurized oxidation method with powdered flake graphite as raw material. A variety of inorganic-reduced graphene oxide composites have been then successfully synthesized through a general solvothermal strategy with the graphene oxide sheets as supports, ethanol as solvent, and metal salts as precursors. After the solvothermal reactions, Ni(OH)2 nanoparticles, Fe2O3 nanorods, W18O49 nanowires, ZnO nanoparticles, and Ag nanoparticles were in situ grown on the surfaces of the graphene oxide sheets, accompanied by effective reduction of graphene oxide to reduced graphene oxide. The as-prepared products have been systematically characterized by electron microscopy, X-ray diffraction, X-ray photoelectron spectrometry, and Raman spectroscopy. The present work opens up a versatile route for preparing the reduced graphene oxide-based composites.