Graphene-wrapped Ag3PO4/LaCO3OH heterostructures for water purification under visible light

We demonstrated a unique synthesis approach of graphene（GR）-wrapped AgPO/LaCOOH（APO/LCO）heterostructures by an in-situ wet chemical method. FESEM analysis reveals the formation of rhombic dodecahedrons of APO decorated with LCO and later wrapped with GR flakes. Optical studies shows two absorption edges corresponding to the band gap energies of APO（2.41 eV） and LCO（4.1 eV）. Considering the absorption edge of the heterostructures in the visible region, the photocatalytic activities of photocatalysts containing different APO/LCO mass ratios were evaluated by the degradation of MB. GR-decorated composite with 20% LCO（APO/LCO20/GR） exhibited the highest photocatalytic activity for MB degradation, with a rate constant, k of 0.541 min. The photocatalytic activity of APO/LCO20/GR more greatly enhanced than those of the individual constituents（APO, LCO, APO/LCO20）. The enhanced photocatalytic activity of the heterostructure can be attributed to the co-catalytic effect of LCO as well as intriguing physicochemical properties of GR. To understand the enhanced photocatalytic activity of the heterostructures the photocatalytic reaction mechanism is proposed in detail. The recyclability of the APO/LCO/GR composite photocatalyst is further evaluated by reusing the catalyst in replicate photocatalytic experiments which shows consistent photocatalytic activity thereby confirms the stability and reusability of heterostructure photocatalyst.

Supersonically sprayed self-aligne d rGO nanosheets and ZnO/ZnMn_(2)O_(4)nanowires for high-energy and high-power-density supercapacitors

Core-shell-type bimetallic oxide and carbon composites comprising zinc oxide(ZnO)nanospheres and zinc manganese oxide(ZnMn_(2)O_(4))nanowires were produced by a hydrothermal method,and supersoni-cally sprayed together with reduced graphene oxide(rGO)nanosheets onto Ni foil to fabricate flexible su-percapacitors.The supersonic impact facilitated the exfoliation of the rGO nanosheets,thereby increasing the surface area and adhesion of the composite particles to the substrate.The rGO nanosheets were vertically aligned during the supersonic impact and formed localized zones,enabling optimal accommodation of the ZnO/ZnMn_(2)O_(4)particles.This localization,with the addition of rGO,reduced the agglomeration of ZnO/ZnMn_(2)O_(4)particles.The molar concentration of MnSO_(4)used in the synthesis of ZnO/ZnMn_(2)O_(4)was varied from 0.05 to 0.15 mol/L to determine the optimal MnSO_(4)concentration that would result in the highest energy storage capacitance.The unique nanostructure of ZnO/ZnMn_(2)O_(4)and the self-alignment of rGO sheets facilitated a favorable environment for high energy storage capability with a specific capaci-tance of 276.3 mF·cm^(−2)at a current density of 0.5 mA·cm^(−2)and an energy density of 98.2μWh·cm^(−2)at a power density of 1600μW·cm^(−2).The width of the potential window was increased to 1.2 V,imply-ing a significant increase in the energy storage capability of the supercapacitor.Capacitance retention of 88%was achieved after 10,000 charge/discharge cycles for the supercapacitor fabricated using an optimal MnSO_(4)concentration(0.10 mol/L)during the composite synthesis.

Wearable heater composites comprising traditional Hanji cellulose fibers coated with graphene,silver nanowires,and PEDOT:PSS via scalable supersonic spraying

Traditional Korean Hanji paper and cotton fabric were introduced as flexible substrates in the fabrication of graphene-coated heaters.Silver nanowires and PEDOT:PSS were added to increase the electrical conductivity of the heaters,thereby enhancing their heating performance.The optimal concentrations of silver nanowires and PEDOT:PSS with respect to that of graphene were identified.These active materials were deposited on flexible Hanji/cotton and non-flexible alumina substrates using supersonic spraying.The proposed Hanji-and cotton-based heaters were light,wearable,stretchable,skin-friendly,and biodegradable.The unyielding alumina-based heater exhibited the highest heating temperature of 275°C at 13 V.Wearable heater bendability and stretchability were tested considering multiple bending and stretching cycles.Moreover,water boiling and fabric drying were successfully performed using the alumina-based heater.The supersonic spraying deposition technique was used to produce writable and patternable heaters.

Bimetallic zeolitic imidazolate framework-derived substrate-free anode with superior cyclability for high-capacity lithium-ion batteries

Freestanding carbon nanofibers loaded with bimetallic hollow nanocage structures were synthesized.The nanocages inherited the rhombic dodecahedral morphology of the zeolitic imidazolate framework(ZIF)precursors,ZIF-8 and ZIF-67.As anode materials for lithium-ion batteries(LIBs),the bimetallic nanocage-loaded freestanding carbon nanofibers effectively buffered volume expansions and alleviated pulverization through their different reduction and oxidation potentials.The higher capacities of the composite anodes arose via the formation of the Li_(x)Zn alloy and Li_(2)O by Zn and Co ions,respectively,and the enhanced conductivity conferred by the carbon nanofibers.A synergistic effect of the composite components toward the strong electrochemical performance(688 m A h·g^(-1)at 1200 m A·g^(-1))of the bimetallic nanocage-loaded fibers was demonstrated through the superior long-term stability of the anode(1048 m A h·g^(-1)after 300 cycles at 100 m A·g^(-1)),suggesting that the fabricated anode can be a promising material for use in portable LIBs.

Reduced graphene oxide supersonically sprayed on wearable fabric and decorated with iron oxide for supercapacitor applications

We demonstrate the fabrication of wearable supercapacitor electrodes.The electrodes were applied to wearable fabric by supersonically spraying the fabric with reduced graphene oxide(r GO)followed by decoration with iron oxide(Fe_(2)O_(3))nanoparticles via a hydrothermal process.The integration of iron oxide with r GO flakes on wearable fabric demonstrates immense potential for applications in high-energystorage devices.The synergetic impact of the intermingled r GO flakes and Fe_(2)O_(3) nanoparticles enhances the charge transport within the composite electrode,ultimately improving the overall electrochemical performance.Taking advantage of the porous nature of the fabric,electrolyte diffusion into the active r GO and Fe_(2)O_(3) materials was significantly enhanced and subsequently increased the electrochemical interfacial activities.The effect of the Fe_(2)O_(3) concentration on the overall electrochemical performance was investigated.The optimal composition yields a specific capacitance of 360 F g^(-1) at a current density of 1 Ag^(-1) with a capacitance retention rate of 89%after 8500 galvanostatic cycles,confirming the long-term stability of the Fe_(2)O_(3)/r GO fabric electrode.

Wearable sensors and supercapacitors using electroplated-Ni/ZnO antibacterial fabric

Herein,nickel nanocones and zinc oxide nanosheets were electroplated onto a fabric to produce multifunctional(wearable,stretchable,washable,hydrophobic,and antibacterial)materials with sensing,heating,and supercapacitive properties.All these functionalities are integrated into a one-layered fabric that can be used as a portable intelligent electronic textile for potential application in healthcare monitoring,smart sportswear,and energy storage.Electroplated nickel enhances the electrical conductivity and thus increases the electron charge transfer for supercapacitor applications.The integration of ZnO with the Ni-plated fabric provides pseudocapacitance via redox reactions with the electrolyte.The resistance of the Ni/ZnO fabric changes in response to external stimuli such as temperature and strain.When voltage is applied,the fabric generates heat through Joule heating,demonstrating its potential application as winter sportswear.The superior mechanical durability of the fabric was confirmed through bending and stretching tests.The hydrophobic surface prevents viruses contained in liquid droplets from infiltrating the fabric.In addition,bacterial growth is inhibited because of the antibacterial properties of the Ni/ZnO fabric and because of Joule heating.The one-layered fabric integrated with such multiple functionalities is expected to be applicable in the development of next-generation portable and wearable electronic textiles in various industries.

Reusable and durable electrostatic air filter based on hybrid metallized microfibers decorated with metal–organic–framework nanocrystals

As global air pollution becomes increasingly severe,various types of fibrous filters have been developed to improve air filter performance.However,fibrous filters have limitations such as high packing density that generally causes high-pressure drop and ultimately deterioration in the filtration efficiency.High-pressure particulate matter precipitators are limited in terms of scope for commercialization because they require high voltage supplies and ozone generators.In this study,we develop fibrous filters with enhanced durability and improved performance using metallized microfibers decorated with metal-organic-framework(MOF)nanocrystals.Not only does the efficiency of the developed filters remain at or above 97%for 0.50-1.5μm PMs but the durability also significantly increases.In addition,using the water purification ability of the MOF,we explore the dye degradation effect of the hybrid microfibers by immersing them into Rhodamine B aqueous solution.In such an experiment the Rhodamine B aqueous solution is completely purified by the presence of the hybrid microfibers under the UV irradiation.