Composite Nanobelts Research Articles

Co/Cu/C multi-doped VOx composite nanobelts for aqueous asymmetric supercapacitors

VOx, possessing multiple stable oxidation states, demonstrates high theoretical capacity, rendering it a promising candidate for supercapacitor electrodes. However, its practical capacity and cyclic performance are hindered by low electrical conductivity and sluggish diffusion kinetics. Incorporating heteroatoms into transition metal oxides has emerged as an effective approach to mitigate these challenges. Nonetheless, the reported capacities and cyclic stabilities of single-element-doped-VOx as supercapacitor electrodes remain unsatisfactory. Herein, we propose a Co/Cu/C multi-doped VOx composite (VCoCuC) nanobelts, which significantly boosts the specific capacity (5.96 C cm−2/398.6 C g−1 @ 10 mA cm−2) and cycling performance (97.1% of the initial capacity after 2,000 cycles @ 60 mA cm−2) compared to samples with only Co/Cu, Co/C, or Cu/C doping. The possible functions of each doping element are discussed. Additionally, an aqueous asymmetric supercapacitor with VCoCuC as the cathode and conductive carbon cloth (CC) as the anode is assembled to demonstrate the potential application of VCoCuC, which delivers high energy density and excellent cyclic performance. These findings highlight the potential for improving the practical capacity and cyclic performance of VOx electrodes via a multi-doping strategy.

Rational design of versatile 1D Ti-O-based core-shell nanostructures for efficient pollutant removal and solar fuel production

The rational design of Ti-O-based nanocomposites is of great importance for achieving efficient solar energy conversion and storage. Herein, novel one-dimensional (1D) K2Ti6O13/TiO2 core-shell nanobelt composites were fabricated by a...

Facile large-scale preparation of vanadium pentoxide -polypyrrole composite for aqueous zinc-ion batteries

Aqueous zinc-ion batteries (ZIBs) have been noted as promising large-scale energy storage systems owing to their cost-effective and environmentally friendly merits. However, the further development of ZIBs is limited by suitable cathodes, which normally suffer from the challengers of cathode dissolution, poor electronic conductivity, and low ion diffusion coefficient. Herein, we adopted a simpler, prone largescale preparation strategy of in situ polymerization at room temperature to prepare V2O5-polypyrrole (V2O5-PPy) nanobelt composite that the V2O5 act as an oxidant for pyrrole (Py) polymerization, and Py in situ polymerized on the V2O5. The V2O5-PPy nanobelt composite contributes to preventing the dissolution of vanadium elements, improving electronic conductivity, and forming oxygen vacancies (Vö). As a result, an excellent initial discharge capacity of 441 mAh g−1 at 0.1 A g−1 and 291 mAh g−1 at a high current density of 5 A g−1 was realized. More importantly, a capacity retention rate of 95.92% after the long-term 2000 cycles at a high current density of 5 A g−1 was achieved. The capacitance control is dominant and accounts for 80.76% at 0.5 mV s−1, and the zinc ion diffusion coefficient during the cycle is 4.4 × 10−8-1.62 × 10−9 cm2 S−1, indicating good kinetics. Our work provides a feasible strategy for the large-scale fabrication of V2O5-PPy for ZIBs.

Charge storage mechanism in vanadium telluride/carbon nanobelts as electroactive material in an aqueous asymmetric supercapacitor

A novel one-step method for fabricating vanadium telluride nanobelt composites for high-performance supercapacitor applications is reported. The nanobelts are realized by direct tellurization of vanadium oxide in-situ formed via decomposition of ammonium metavanadate in argon atmosphere. Use of melamine as precursor helps in forming graphitic carbon layers during pyrolization on which the nanobelts are grafted. Morphological analysis suggests interconnected nanobelts of ∼23.0 nm width coming out of carbon structure. As pseudocapacitive electrode, vanadium telluride/carbon (C) composite exhibits interesting electrochemical performance within a potential window of 0–1.0 V in 1.0 M sodium sulfate electrolyte along with excellent capacitance retention during 5000 cycles. In-depth analysis suggests that the charge storage mechanism in the composite is governed by both diffusion-controlled and diffusion-independent processes with the former dominating at slower scan rates and later at faster scan rates. The asymmetric supercapacitor assembled using vanadium telluride/C and activated charcoal (AC) as respective positive and negative electrodes exhibited an energy/power combination of 19.3 Wh/kg and 1.8 kW/kg within a potential window of 0–1.8 V in aqueous electrolyte. This strategy to improve capacitance along with potential window in an aqueous electrolyte would facilitate development of high-performance energy storage devices with metal chalcogenides.

Silver nanoparticle-embedded titania nanobelts with tunable electronic band structures and plasmonic resonance for photovoltaic application

Metallic silver nanoparticle (NP)-embedded single-crystalline titania (Ag@TiO2) nanobelts have been prepared by a new process with use of sodium titanates sequentially from ion exchange, thermal hydrogenation to post-calcination. The structural transformation involved and their morphology were characterized. This work explored photovoltaic efficiency of these composite nanobelts as anode materials in dye-sensitized solar cells and their electronic and energy band properties, which correlate with the Ag content. Optical absorption and photoluminescence analyses reveal core Ag NP-induced localized surface plasmon resonance (LSPR) and mediated electron transfer within the titania shell. According to Mott-Schottky analysis, the Ag addition causes an increase in the donor density and an upshift in the flat-band potential of the oxide host. The investigated Ag@TiO2 cells produced higher photocurrents and open-circuit voltages than the bare TiO2 one, and the best performance was attained with a marked enhancement by 72% in the photovoltaic efficiency. As indicated by electrochemical impedance analysis, the Ag-added nanobelts are beneficial to rapid electron diffusion and electron lifetime, so that they promote charge collection efficiency. Synergistic combination of plasmonic resonance, electronic conduction and Fermi-level upshift is a plausible strategy to functionalize the one-dimensional core-shell Ag@TiO2 nanostructures for optoelectronic applications.

Effect of thermal treatment temperature on catalytic performance of Pt/TiO2 nanobelt composite for HCHO oxidation

TiO2 nanobelts were prepared by hydrothermal synthesis and acid treatment, then calcination at different temperatures. And subsequently Pt nanoparticles were deposited on the TiO2 nanobelts. Pt/TiO2 catalytic properties were investigated in the oxidation of formaldehyde. These catalysts were characterized by various techniques and the characterization results showed that the applied thermal treatment temperature greatly influenced the phase composition and surface structure of TiO2 nanobelts, as well as the number of oxygen vacancies and hydroxyl groups on the surface. The Pt/TiO2 nanobelts thermally treated at 600°C had more oxygen vacancies, which were conducive to the activation of adsorbed oxygen, formed more Ti-(OH)x-Pt species, and showed higher catalytic activity. At 25°C and relative humidity of 55%, the conversion of formaldehyde reached 91.6%.

NIR-responsive MXene nanobelts for wound healing

Effectively achieving wound healing is a great challenge. Herein, we facilely prepared temperature-responsive MXene nanobelt fibers (T-RMFs) carrying vitamin E with a controllable release ability for wound healing. These T-RMFs were composed of MXene nanosheets spread along polyacrylonitrile and polyvinylpyrrolidone composite nanobelts together with a thermosensitive PAAV- coating layer. The high mass loading and high surface area of the MXene nanosheets endow the T-RMFs with excellent photothermal properties. The temperature could be easily controlled by near-infrared (NIR) irradiation exposure, and then the thermoresponsive polymeric coating layer relaxed the interface to dissolve vitamin E and promote vitamin E release. The T-RMFs demonstrated excellent biocompatibility and wound-healing functions in cellular and animal tests. The facile method, high mass loading, high surface area, excellent wound-healing functions, interesting nanosheet/nanobelt structure, mass production potential, and NIR responsive properties of these T-RMFs indicate the great potential of our nanobelts for wound healing, tissue engineering, and much broader application areas. This facile nanosheet/nanobelt preparation strategy paves a new way for nanomaterial fabrication and applications.

Dual mode competitive electrochemical immunoassay for dibutyl phthalate detection based on PEI functionalized nitrogen doped graphene-CoSe2/gold nanowires and thionine-Au@Pt core-shell

In this work, a sensitive dual mode competitive electrochemical immunosensor based on differential pulse voltammetry (DPV) and square wave voltammetry (SWV) response modes for quantitative determination of dibutyl phthalate (DBP) was successfully established. According to diethylenetriamine (DETA) assisted hydrothermal strategy, a novel N-doped graphene/CoSe2 nanobelt composite was prepared. Afterwards, PEI functionalized NG-CoSe2 and gold nanowires (AuNWs) were further compounded as a preliminary signal amplification platform for immunosensor. Thionine (Thi)-loaded [email protected] and secondary antibody (Ab2) connected as a signal label. The immobilized coating antigen DBP-BSA and the DBP compete for limited antibody binding sites. The concentration of DBP can be determined by DPV detect the Thi signal loaded on the [email protected]2 label. It can also be determined by SWV mode to detect the current generated by the reaction system of H2O2 and o-phenylenediamine (o-PD) catalyzed by [email protected] with peroxidase like properties. Under optimum conditions, the linear ranges of the DPV and SWV modes were 1 pg mL−1∼1 μg mL−1. And LOD were 0.486 pg mL-1 (DPV) and 0.711 pg mL-1 (SWV), respectively. Besides, it exhibited outstanding selectivity, reproducibility, stability and can be used for sensitive detection of DBP in real samples.

Field emission from geometrically modulated tungsten-nickel sulfide / graphitic carbon nanobelts on Si microchannel plates

The low efficiency and instability of electron emission from two-dimensional (2D) materials such as WS2 and NiS hamper application to vacuum microelectronic devices. Although nickel-based alloys have many favorable physicochemical properties suitable for nanoelectronics, electron field emission (FE) from heterostructures comprising tungsten-nickel sulfide alloys and graphite carbon (WNi–S/C) has been seldom studied because it is difficult to fabricate the nanostructures in situ. In this work, field emitters composed of the WNi–S/C nanobelt composite are produced on Si microchannel plates (WNi–S/C@Si) hydrothermally. The structure has a porous and vertically aligned 3D morphology in addition to excellent adhesion strength with the substrate. Geometrical modulation of the WNi–S/C@Si is performed by changing the hydrothermal reaction temperature and an ultralow turn-on electric field of 0.51 V μm−1 for a current density 0.1 mA cm−2, threshold electric field of 0.65 V μm−1 for a current density of 1 mA cm−2, and stability of 97.1% for 8 h are accomplished. The related mechanisms are investigated and discussed. Moreover, finite element simulation shows that not only the shape of the nanostructures but also the high aspect plays a key role in reducing screen effects. These outstanding properties suggest large potential in high-performance FE and vacuum nanodevices.

Effective visible-light-driven photocatalytic degradation of 17α-ethynylestradiol by crosslinked CdS nano-rod/TiO2 (B) nano-belt composite

New CdS nano-rod/TiO2 (B) nano-belt composites (denoted as CdS-NR/TiO2 (B)-NB) were successfully prepared via a two-step hydrothermal process. The chemical composition and structure of synthesized materials were characterized by X-ray diffraction (XRD), field emission scanning microscopy (FESEM), transmission electron microscopy (TEM), element map, UV visible diffuse reflectance spectroscopy (UV–vis DRS) and photoluminescence spectroscopy (PL). The prepared samples were used to remove 17α-ethynylestradiol (EE2) under visible light irradiation, which has most potent estrogenic activity and resists to biodegradation. The results show that the B-type TiO2 (TiO2(B)) nano-belts are crosslinked with CdS nano-rods to form heterojunction with higher removal rate (92.00%) than pure CdS nanorods (55.67%) for 3 mg/L EE2 within 120 min when the mass ratio of CdS nanorods to TiO2 (B) nanobelts is 1:15. The degradation rate constant of EE2 over CdS-NR/TiO2 (B)-NB (0.001763 min−1) is 3 times higher than pure CdS-NR (0.00567 min−1) under visible light irradiation. Charge generation, migration and possible photocatalytic mechanism of EE2 on CdS-NR/TiO2 (B)-NB photocatalyst has been proposed based on the theoretical calculation and reactive species trapping experimental results.

MnSe2/Se Composite Nanobelts as an Improved Performance Anode for Lithium Storage

MnSe2/Se Composite Nanobelts as an Improved Performance Anode for Lithium Storage

Hydroxylated carbon nanotube/carbon nitride nanobelt composites with enhanced photooxidation and H2 evolution efficiency

Hydroxylated multi-walled carbon nanotubes modified with a carbon nitride nanobelt (HCNT/CNN) were successfully fabricated by using combined solvothermal and ultrasonic methods to improve both tetracycline hydrochloride (TC) degradation and H2 evolution. The well-designed photocatalysts exhibited a wide light absorption range, low photoluminescence (PL) intensity, high photocurrent, and small electrochemical impedance spectroscopy (EIS) arc; these properties significantly enhanced the overall photocatalytic efficiency. At the optimal loading of HCNT (0.05 wt%), the resulting HCNT/CNN exhibited the highest TC photocatalytic degradation rate, and the H2 production rate reached 175.5 μmol g−1 h−1. Compared to the multi-walled carbon nanotube modified carbon nitride nanobelt, the TC photocatalytic degradation rate and H2 production rate of HCNT/CNN increased by factors of 3 and 4.2, respectively. This significantly enhanced performance can be ascribed to the formation of hydrogen bonds between HCNT and CNN, which facilitates the electron transfer from the CNN to the HCNT surface, thereby accelerating the separation of photogenerated charge carriers. Moreover, the possible mechanism of the improved photocatalytic performance for the HCNT/CNN composites was proposed. This study provides the guidance for the design of novel carbon nitride nanobelt-based photocatalysts for wastewater purification and H2 evolution.

Electrochemical Characteristics of Li4Ti5O12/Ag Composite Nanobelts Prepared via Electrospinning

Li4Ti5O12/Ag composite nanobelts with an average width of ca. 1.12 μm were successfully synthesized via a facile electrospinning, and the average width is ca. 1.12 μm. The Li4Ti5O12/Ag composites show perfect initial discharge capacity (178.72 mA h g–1 at 0.1 C), better rate capability (131.70 mA h g–1 after cycled at 15 C) and super cycling stability (172.21 mA h g–1 after 100 cycles at 0.2 C) compared to pure Li4Ti5O12 nanobelts when used as anode materials for lithium ion batteries. The excellent electrochemical performance is explained by the nanostructure of obtained samples which could provide an effective ion and electron transport in the longitudinal direction. The addition of Ag could enhance charge transfer due to increased electronic conductivity. Our new findings provide an effective way to improve the electrochemical performance of Li4Ti5O12 anode materials for lithium ion batteries.

Fast Na‐Ion Intercalation in Zinc Vanadate for High‐Performance Na‐Ion Hybrid Capacitor

AbstractNa‐ion hybrid capacitors are an emerging class of inexpensive and sustainable devices that combine the high energy of batteries with the high power of capacitors. However, their development is strongly impeded by a limited choice of electrode materials that display good electrochemical kinetics and long‐term cyclability. Here, a reduced graphene oxide–Zn0.25V2O5·nH2O nanobelt composite is introduced as a high power anode for Na‐ion batteries and Na‐ion hybrid capacitors. The composite material possesses fast Na‐ion intercalation kinetics, high electronic conductivity, and small volume change during Na‐ion storage, which lead to outstanding rate capability and cycling stability in half‐cell tests. Pairing it with a hard salt–templated, highly ordered mesoporous carbon as a high‐performance capacitive cathode results in a Na‐ion hybrid capacitor, which delivers a high energy density (88.7 Wh kg−1 at 223 W kg−1), a high power density (12552 W kg−1 with 13.2 Wh kg−1 retained), and an impressive cycling performance (31.7 Wh kg−1 (i.e., 87%) retained after 2000 cycles at 1 A g−1). This work explores zinc vanadate, a typical example of a layered metal vanadate, as an intercalation anode material with high pseudocapacitance for Na‐ion hybrid capacitors, which may open a promising direction for high‐rate Na‐ion storage.

Flexible films of poly(3,4-ethylenedioxythiophene):Poly(styrenesulfonate)/SnS nanobelt thermoelectric composites

Organic polymer/inorganic thermoelectric (TE) composites are emerging green energy materials for diverse applications including harvesting waste or low-quality heat, local cooling, sensing and wearable electronics. Here, we report flexible films of new TE composites by employment of SnS nanobelt into polymer matrix. First, the SnS nanobelts with high purity were prepared by a convenient hydrothermal process. Then, the poly (3,4-ethylenediox-ythiophene): poly (styrenesulfonate) (PEDOT:PSS)/SnS nanobelt composites were obtained by a solution mixing procedure aided by ultrasonication. The structure and morphology of the SnS nanobelts as well as the PEDOT:PSS/SnS composites were characterized by X-ray diffraction (XRD) and field-emission scanning electroscopic (FESEM) techniques. The effects of the SnS content and the dispersing agent (organic solvent) on the dispersion state and the TE performance for the composites were investigated. The highest power factor at room temperature reached 27.8 ± 0.5 μW m−1 K−2 for the PEDOT:PSS/SnS nanobelt composite prepared in N,N-Dimethylformamide. The present study opens a novel avenue to exploit of excellent polymer TE composites by introduction of inorganic nanoparticles with large Seebeck coefficients.

La2O2CN2:Yb3+/Tm3+ nanofibers and nanobelts: novel fabrication technique, structure and upconversion luminescence

For the first time, La2O2CN2:Yb3+/Tm3+ upconversion luminescence nanofibers and nanobelts were successfully fabricated via cyanamidation of the respective relevant La2O3:Yb3+/Tm3+ nanofibers and nanobelts which were obtained by calcining the electrospinning made PVP/[La(NO3)3+Yb(NO3)3+Tm(NO3)3] composite nanofibers and nanobelts. The morphologies, structures, and properties of the nanofibers and nanobelts are investigated. The diameters of La2O2CN2:Yb3+/Tm3+ nanofibers and width of La2O2CN2:Yb3+/Tm3+ nanobelts with the thickness of 112 nm are 109 ± 4.3 nm and 1.8 ± 0.2 μm at 95% confidence level, respectively. Upconversion luminescent analysis manifests that La2O2CN2:Yb3+/Tm3+ nanofibers and nanobelts emit intense blue emissions around 476 nm corresponding to 1G4→3H6 energy level transitions of Tm3+ ions under the excitation of a 980-nm diode laser. For the La2O2CN2:30%Yb3+/x%Tm3+ nanofibers, the blue emission intensity increases when the Tm3+ concentration is increased from 0.1 to 0.5% and then decreases as the Tm3+ concentration is further increased from 0.5 to 1.0%, so the Tm3+ optimum concentration is 0.5%. For the La2O2CN2:y%Yb3+/0.5%Tm3+ nanofibers, when the concentration of Tm3+ is fixed at 0.5%, the blue emission intensity increases when the Yb3+ concentration is increased from 5 to 30% and then decreases as the Yb3+ concentration is further increased from 30 to 40%. Therefore, the optimum concentration of Yb3+ is 30%. Thus, the optimum molar concentration ratio of Yb3+ to Tm3+ ions is 60:1 in the as-prepared La2O2CN2:Yb3+/Tm3+ nanofibers. The formation mechanisms of the La2O2CN2:Yb3+/Tm3+ nanostructures are also proposed. The novel technique can be applied to prepare other rare earth oxycyanamide nanostructures of various morphologies.

Au/Co 3 O 4 /CeO 2 heterostructures: Morphology controlling, junction formation and enhanced catalysis performance

Abstract Co 3 O 4 nanochain and Co 3 O 4 /CeO 2 heterostructures were prepared via an electrospinning process and subsequent calcination. The formation and shape evolution from Co 3 O 4 nanochains to Co 3 O 4 /CeO 2 composite nanobelts were investigated, suggesting that both components and preparation parameters play important roles in resulted morphology and properties. Homogeneous Co 3 O 4 /CeO 2 junctions in belt samples were formed towards enhanced catalysis performance. Well-dispersed Au nanoparticles were deposited on Co 3 O 4 /CeO 2 composite nanostructures or doped inside through reduction and direct calcination route method, respectively. The loading of Au nanoparticles significantly enhanced catalytic performance with onset CO conversion at 100 °C and resulted in CO conversion over at 127 °C.

Facile electrospinning preparation and luminescence performance of color adjustable Y3Al5O12:Dy3+ nanobelts

Novel nanostructures of Y3Al5O12:Dy3+ (denoted as YAG:Dy3+ for short) nanobelts were fabricated by calcination of the relevant electrospun PVP/[Y(NO3)3 + Dy(NO3)3 + Al(NO3)3] composite nanobelts. YAG:Dy3+ nanobelts are cubic in structure with space group of Ia3d. The thickness and width of the YAG:Dy3+ nanobelts are respectively 112.45 nm and 3.85 ± 0.90 μm under the 95% confidence level. Under the excitation of 352-nm ultraviolet light, the emission bands in the 450–460 nm (at 452 nm) blue region, 470–500 nm (at 484 nm) blue region and 570–600 nm (at 583 nm) yellow region corresponding to 4I15/2 → 6H15/2, 4F9/2 → 6H15/2 and 4F9/2 → 6H13/2 energy levels transitions of Dy3+ ions, respectively. It is found that the optimum doping molar concentration of Dy3+ ions for YAG:Dy3+ nanobelts is 1%. CIE analysis demonstrates that the emitting colors of YAG:Dy3+ nanobelts are located in the blue region and color-tuned luminescence can be obtained by changing doping concentration of Dy3+, which could be applied in the field of optical telecommunication and optoelectronic devices. The possible formation mechanism of YAG:Dy3+ nanobelts is also proposed.

Electrospinning preparation and photoluminescence properties of Y3Al5O12:Ce3+, Tb3+ nanobelts

Novel nanostructure of Y3Al5O12:Ce3+, Tb3+ (denoted as YAG:Ce3+, Tb3+ for short) nanobelts and nanofibers were fabricated by calcination of the respective electrospun PVP/[Y(NO3)3 + Ce(NO3)3 + Tb(NO3)3 + Al(NO3)3] composite nanobelts. YAG:Ce3+, Tb3+ nanobelts are cubic in structure with space group of Ia3d. The thickness and width of the YAG:Ce3+, Tb3+ nanobelts are respectively 118 nm and 4.09 ± 0.41 μm. The excitation spectra detected of 520 nm for Ce3+ emission represented 4f 8 → 4f 75d transition band at 273 nm by Tb3+ and other two bands by Ce3+. When excited with a UV light of 273 nm, YAG:Ce3+, Tb3+ nanobelts showed the characteristic Tb3+ peaks, as well as Ce3+ emission peak. The results concluded that the energy transfer pathway in YAG:Ce3+, Tb3+ nanobelts system was one-way from Tb3+ to Ce3+. Commission International del’Eclairage chromaticity coordinates indicated that the emission colors of YAG:Ce3+, Tb3+ nanobelts were tunable by changing the concentration of doping Ce3+, which could be applied in the field of optical telecommunication and optoelectronic devices. The possible formation mechanism of YAG:Ce3+, Tb3+ nanobelts was also proposed.

Bifunctional Ag/C3N4.5 composite nanobelts for photocatalysis and antibacterium

Multiple functions can be achieved in carbon nitride-based composite nanomaterials by tuning their components and structures. Here, we report on a large-scale synthesis of novel bifunctional Ag/C3N4.5 composite nanobelts (CNBs) with efficient photocatalytic and antibacterial activity. The Ag/C3N4.5 CNBs were synthesized in high yield by a two-step route including a homogeneous precipitation process and a subsequent calcination treatment. The structural, morphological, compositional, and spectroscopic characterizations revealed that the Ag/C3N4.5 CNBs are composed of N-deficient melem ultrathin nanobelts and crystalline Ag nanoparticles attached to the surface of the nanobelts with good contact. The band gap of the Ag/C3N4.5 CNBs is determined to be about 3.04 eV. The efficient photocatalytic and antibacterial activities of the composite nanomaterials are verified by testing the degradation of Rhodamine B (RhB) and the inhibition zone to bacterium E. coli. The work provides a facile route to bifunctional carbon nitride-based composites with potential applications in the fields of the environment and biology.