Single crystal zinc oxide nanocombs were synthesized in bulk quantity by vapor phase transport. A glucose biosensor was constructed using these nanocombs as supporting materials for glucose oxidase ͑GO x ͒ loading. The zinc oxide nanocomb glucose biosensor showed a high sensitivity ͑15.33 A/cm 2 mM͒ for glucose detection and high affinity of GO x to glucose ͑the apparent Michaelis-Menten constant K M app = 2.19 mM͒. The detection limit measured was 0.02 mM. These results demonstrate that zinc oxide nanostructures have potential applications in biosensors.

We report herein a glucose biosensor based on glucose oxidase (GOx) immobilized on ZnO nanorod array grown by hydrothermal decomposition. In a phosphate buffer solution with a pH value of 7.4, negatively charged GOx was immobilized on positively charged ZnO nanorods through electrostatic interaction. At an applied potential of +0.8V versus Ag∕AgCl reference electrode, ZnO nanorods based biosensor presented a high and reproducible sensitivity of 23.1μAcm−2mM−1 with a response time of less than 5s. The biosensor shows a linear range from 0.01to3.45mM and an experiment limit of detection of 0.01mM. An apparent Michaelis-Menten constant of 2.9mM shows a high affinity between glucose and GOx immobilized on ZnO nanorods.

MoS is a promising electrode material for energy storage. However, the intrinsic multilayer pure metallic MoS (M-MoS) has not been investigated for use in supercapacitors. Here, an ultrafast rate supercapacitor with extraordinary capacitance using a multilayer M-MoS-HO system is first investigated. Intrinsic M-MoS with a monolayer of water molecules covering both sides of nanosheets is obtained through a hydrothermal method with water as solvent. The super electrical conductivity of the as-prepared pure M-MoS is beneficial to electron transport for high power supercapacitor. Meanwhile, nanochannels between the layers of M-MoS-HO with a distance of ∼1.18 nm are favorable for increasing the specific space for ion diffusion and enlarging the surface area for ion adsorption. By virtue of this, M-MoS-HO reaches a high capacitance of 380 F/g at a scan rate of 5 mV/s and still maintains 105 F/g at scan rate of 10 V/s. Furthermore, the specific capacitance of the symmetric supercapacitor based on M-MoS-HO electrodes retain a value as high as 249 F/g under 50 mV/s. These findings suggest that multilayered M-MoS-HO system with ion accessible large nanochannels and efficient charge transport provide an efficient energy storage strategy for ultrafast supercapacitors.

by the large volume change and the poor intrinsic conductivity with a direct bandgap of ≈1.9 eV significantly inhibits the further applications of 2H MoS 2 on lithium-ion batteries. [8,9] One of the best and typical strategies to ameliorate the structural stability and electrical conductivity of MoS 2 based anode is to fabricate hybrid 2H MoS 2 nanocomposites with conductive carbonaceous materials, such as carbon fibers, graphene, and carbon nanotubes. These hybrid MoS 2 -carbon nano composites (MCNs) could deliver a decent capacity of ≈900 mA h g −1 at 1 A g −1 current density on lithium-ion batteries for 100 cycles. [2,10,11] Unfortunately, this strategy also induces new constraints to the MCNs' applications on lithium-ion batteries, such as reducing the mass loading of MoS 2 , consuming more electrolytes, raising the electrode cost, and increasing the reaction barrier between lithium-ion and MoS 2 . [12] Even though carbon source can improve the conductivity of the electrode, the intrinsic insulating property of 2H MoS 2 remains unchanged, which will significantly limit its rate performance and impede the utilization of the active MoS 2 . Recently, the metastable metallic phase (1T or 1T′) MoS 2 has emerged with promising potential on lithium-ion storage field. As reported, [8,[13][14][15] benefited from its different Mo and S atom coordination of octahedral structure with dense intercalation sites, metallic phase MoS 2 owns five orders of magnitude higher electrical conductivity than that of 2H MoS 2 . This high intrinsic conductivity will be beneficial for the performance of metallic MoS 2 electrode in the following two aspects. On one hand, pure metallic MoS 2 can be directly applied as an anode electrode on lithium-ion batteries without adding any conductive carbon sources, which would facilitate the electrochemical storage fundamental mechanism studying of metallic MoS 2 . On the other hand, the utilization of active MoS 2 can also be maximized, and the lithium-ion charge/discharge capacity could be tremendously enhanced at high current density, therefore intensely improves the rate performance as well as the reversible capacity of metallic MoS 2 as an anode electrode. However, the conventional preparation methods of metallic MoS 2 by alkali metal intercalation and exfoliation are complicated, unstable, and dangerous. [13] Recent reports provided several new strategies to prepare metallic MoS 2 by solvothermal method, [9,16,17] which stabilized the metallic MoS 2 by interlayer Metallic phase molybdenum disulfide (MoS 2 ) is well known for orders of magnitude higher conductivity than 2H semiconducting phase MoS 2 . Herein, for the first time, the authors design and fabricate a novel porous nanotube assembled with vertically aligned metallic MoS 2 nanosheets by using the scalable solvothermal method. This metallic nanotube has the following advantages: (i) intrinsic high electrical conductivity that promotes the rate performance of battery and eliminates the using of conductive additive; (ii) hierarchical, ...

This work studies for the first time the metallic 1T MoS 2 sandwich grown on graphene tube as a freestanding intercalation anode for promising sodiumion batteries (SIBs). Sodium is earth-abundant and readily accessible. Compared to lithium, the main challenge of sodium-ion batteries is its sluggish ion diffusion kinetic. The freestanding, porous, hollow structure of the electrode allows maximum electrolyte accessibility to benefit the transportation of Na + ions. Meanwhile, the metallic MoS 2 provides excellent electron conductivity. The obtained 1T MoS 2 electrode exhibits excellent electrochemical performance: a high reversible capacity of 313 mAh g −1 at a current density of 0.05 A g −1 after 200 cycles and a high rate capability of 175 mAh g −1 at 2 A g −1 . The underlying mechanism of high rate performance of 1T MoS 2 for SIBs is the high electrical conductivity and excellent ion accessibility. This study sheds light on using the 1T MoS 2 as a novel anode for SIBs.

The fast spread of SARS-CoV-2 has severely threatened the public health. Establishing a sensitive method for SARS-CoV-2 detection is of great significance to contain the worldwide pandemic. Here, we develop a graphene field-effect transistor (g-FET) biosensor and realize ultrasensitive SARS-CoV-2 antibody detection with a limit of detection (LoD) down to 10 −18 M (equivalent to 10 −16 g mL −1 ) level. The g-FETs are modified with spike S1 proteins, and the SARS-CoV-2 antibody biorecognition events occur in the vicinity of the graphene surface, yielding an LoD of ∼150 antibodies in 100 μL full serum, which is the lowest LoD value of antibody detection. The diagnoses time is down to 2 min for detecting clinical serum samples. As such, the g-FETs leverage rapid and precise SARS-CoV-2 screening and also hold great promise in prevention and control of other epidemic outbreaks in the future.

Due to ultra-high reactivity, direct determination of free radicals, especially hydroxyl radical (•OH) with ultra-short lifetime, by field-effect transistor (FET) sensors remains a challenge, which hampers evaluating the role that free radical plays in physiological and pathological processes. Here, we develop a •OH FET sensor with a graphene channel functionalized by metal ion indicators. At the electrolyte/graphene interface, highly reactive •OH cuts the cysteamine to release the metal ions, resulting in surface charge de-doping and a current response. By this inner-cutting strategy, the •OH is selectively detected with a concentration down to 10 −9 M. Quantitative metal ion doping enables modulation of the device sensitivity and a quasi-quantitative detection of •OH generated in aqueous solution or from living cells. Owing to its high sensitivity, selectivity, real-time label-free response, capability for quasi-quantitative detection and user-friendly portable feature, it is valuable in biological research, human health, environmental monitoring, etc.

Thermally insulating materials, made from earth-abundant and sustainable resources, are highly desirable in the sustainable construction of energy efficient buildings. Cellulose from wood has long been recognized for these characteristics. However, cellulose can be a flammability hazard, and for construction this has been addressed via chemical treatment such as that with halogen and/or phosphorus, which leads to further environmental concerns. Fortunately, the structure of cellulose lends itself well to chemical modification, giving great potential to explore interaction with other compounds. Thus, in this study, cellulose nanofibers (CNFs) were nano-wrapped with ultrathin 1T phase molybdenum disulfide (MoS) nanosheets via chemical crosslinking, to produce an aerogel. Thermal and combustion characterization revealed highly desirable properties (thermal conductivity k = 28.09 mW m K, insulation R value = 5.2, limit oxygen index (LOI) = 34.7%, total heat release = 0.4 MJ m). Vertical burning tests also demonstrated excellent fire retardant and self-extinguishing capabilities. Raman spectra further revealed that MoS remained unscathed after 30 seconds of burning in a 1300 °C butane flame. Considering the inherently low density of this material, there is significant opportunity for its usage in a number of insulating applications demanding specific fire resistance properties.