The strontium ferrite nanorods/graphene were synthesized by a by a facile surfactant assisted hydrothermal method, which exhibited outstanding energy density and power density characteristics.
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•The SrFe12O19 NR/G composites were prepared by a facile surfactant assisted hydrothermal method.•The influence of component ratio on electrochemical performances of SrFe12O19 NR/G composites was thoroughly studied.•The SrFe12O19 NR/G composites exhibited outstanding energy densities and power densities.
The exploration of efficient and stable electrode materials is important for supercapacitors. Composite electrode materials are promising candidates for supercapacitors since single component materials cannot satisfy the dual needs of high energy density and power density. In this study, uniform strontium ferrite nanorods are grown on graphene by a facile surfactant assisted hydrothermal method. The resultant SrFe12O19 nanorods/graphene (SrFe12O19 NR/G) composites combine the merits of both SrFe12O19 and graphene, and the SrFe12O19 NR/G based supercapacitors exhibit specific capacitances of 681.2 and 450.9 F g−1 at 1 and 20 A g−1, respectively, and 95.5% of capacitance retention after 10,000 cycles at 1 A g−1. Moreover, they exhibit outstanding energy density and power density characteristics (47.3 Wh kg−1 at 500.9 W kg−1 and 31.3 Wh kg−1 at 10247.7 W kg−1). In addition, the influence of component ratio on the electrochemical performances of SrFe12O19 NR/G composites is thoroughly studied. Finally, the energy storage behavior and mechanism of as-obtained SrFe12O19 NR/G composites are investigated to further understand their enhanced capacitive performances. This work not only provides a new supercapacitor electrode material, but also offers an idea that can be used for the construction of composite electrode materials.
The use of seed‐mediated growth as a versatile approach to the synthesis of penta‐twinned Cu nanorods with uniform diameters and controllable aspect ratios is reported. The success of this approach ...relies on our recent synthesis of uniform Pd decahedra, with sizes in the range of 6–20 nm. The Pd decahedral seeds can direct the heterogeneous nucleation and growth of Cu along the fivefold axis to produce nanorods with uniform diameters defined by the lateral dimension of the original seeds. Due to a large mismatch in the lattice constants between Cu and Pd (7.1%), the deposited Cu is forced to grow along one side of the Pd decahedral seed, generating a nanorod with an asymmetric distribution of Cu, with the Pd seed situated at one of the two ends. According to extinction spectra, the as‐obtained Cu nanorods can be stored in water under the ambient conditions for at least six months without noticeable degradation. This excellent stability allows us to systematically investigate the size‐dependent surface plasmon resonance properties of the penta‐twinned Cu nanorods. With the nanorod transverse modes positioned at 560 nm, the longitudinal modes can be readily tuned from the visible to the near‐infrared region by controlling the aspect ratio.
Pd decahedra are used as seeds to direct the nucleation and growth of Cu along the fivefold axis to produce penta‐twinned Cu nanorods with uniform diameters and controllable aspect ratios. The Cu atoms only grow along one side of the decahedral seed, generating a Cu nanorod with the Pd seed at one of the two ends.
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•A cellular structure and synergistic electric/magnetic losses of the EMW contribute to outstanding EMW absorption.•The MXene/graphene oxide/Co3O4 nanorods foam shows an RLmin ...of − 71.87 dB and a maximum EAB of 6.88 GHz.•The reduction value of radar cross-section achieves up to 33.07 dBm2 at a scattering angle of 90°.
The biggest challenge for electromagnetic wave absorption (EMA) devices is to simultaneously achieve high reflection loss (RL), wide absorption bandwidth, and ultrathin thickness. According to the EMA mechanism of the electromagnetic wave (EMW) absorbers, exceptional EMA properties can be achieved by a combination of three-dimensional (3D) cellular structure and synergistically electric/magnetic losses of the electromagnetic energy. In this study, an MXene/graphene oxide (GO)/Co3O4 nanorods (NRs) (MGCR) aerogel composed of two-dimensional (2D) MXene and GO nanosheets, and one-dimensional (1D) Co3O4 NRs was developed to achieve desirable EMA properties. Here, MXene and GO manipulate the dielectric loss, and the Co3O4 NRs provide magnetic loss. The MGCR aerogel shows excellent EMA performances with an impressive minimum RL (RLmin) of − 71.87 dB at a thickness of 2.07 mm and an outstanding maximum effective absorption bandwidth (EAB) of 6.88 GHz with a density of 9 mg cm−3. And the RL ≤ − 10 dB is obtained in S-band (2–4 GHz), C-band (4–8 GHz), X-band (8–12 GHz), and Ku-band (12–18 GHz) by adjusting the thickness between 2 and 6 mm. In addition, computer simulation technology (CST) was employed to verify the radar cross-section (RCS) reduction of the MGCR in the far-field. The strongest RCS reduction value of the MGCR aerogel achieves up to 33.07 dBm2 at a scattering angle of 90°. This research provides a novel strategy for designing MXene-based electromagnetic absorbers by coupling 1D anisotropically magnetic materials with dielectric materials.
Recently, a new class of 2D materials, i.e., transition metal carbides, nitrides, and carbonitrides known as MXenes, is unveiled with more than 20 types reported one after another. Since they are ...flexible and conductive, MXenes are expected to compete with graphene and other 2D materials in many applications. Here, a general route is reported to simple self‐assembly of transition metal oxide (TMO) nanostructures, including TiO2 nanorods and SnO2 nanowires, on MXene (Ti3C2) nanosheets through van der Waals interactions. The MXene nanosheets, acting as the underlying substrate, not only enable reversible electron and ion transport at the interface but also prevent the TMO nanostructures from aggregation during lithiation/delithiation. The TMO nanostructures, in turn, serve as the spacer to prevent the MXene nanosheets from restacking, thus preserving the active areas from being lost. More importantly, they can contribute extraordinary electrochemical properties, offering short lithium diffusion pathways and additional active sites. The resulting TiO2/MXene and SnO2/MXene heterostructures exhibit superior high‐rate performance, making them promising high‐power and high‐energy anode materials for lithium‐ion batteries.
Transition metal oxide (TMO) nanostructures are self‐assembled on MXene nanosheets in tetrahydrofuran through van der Waals interactions, resulting in novel TMO/MXene heterostructures. Due to remarkable morphological and functional synergy, the TMO/MXene heterostructures exhibit superior high‐rate performance, which rank them as promising anode materials for fast and stable lithium storage.
Heterostructure nanorods are constructed by interconnected NiSe2 and CoSe2 nanoparticles based on cone-like ZIF-L. Due to the design of the granular nanorod arrays structure, the hierarchical ...flexible nanoarrays reflect rich redox active sites, outstanding capacitance performance and excellent structural stability.
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•The one-dimensional (Ni, Co)Se2 nanoarrays based on cone-like ZIF-L were successfully designed.•A single nanorod is composed of interconnected NiSe2 and CoSe2 nanoparticles.•Due to the design of granular heterostructure, the hierarchical flexible nanoarrays reflect rich redox active sites.•The hybrid supercapacitor of CF@(Ni,Co)Se2//AC achieves an excellent electrochemical property.
The construction of heterostructure could enhance the electron transfer efficiency and increase the number of active sites, which can further develop high-performance electrode materials of supercapacitors. Herein, (Ni, Co)Se2 nanorod arrays were prepared based on the NiCo-LDH derived from a conical ZIF-L. Significantly, the single nanorod is composed of interconnected NiSe2 and CoSe2 nanoparticles, the heterostructure can expose higher conductivity, more sufficient redox reaction active sites and larger specific surface area. The as-obtained CF@(Ni, Co)Se2 achieved a high specific capacity of 188.8 mAh g−1 at the current density of 1.0 A g−1 and an outstanding cycling stability with a high capacity retention of 90% after 8000 cycles. Finally, an hybrid supercapacitor device composed of activated carbon (AC) as negative electrode and CF@(Ni, Co)Se2 as positive electrode was designed, which revealed an ideal voltage window of 0–1.6 V and exhibited a great energy density of 36.02 Wh kg−1 at the power density of 800 W kg−1, such surpassing energy storage characteristics evidently testify that (Ni, Co)Se2 nanorod arrays can be as the potential electrode material to promote the development of high-performance supercapacitors.
In this study, novel Gadolinium doped WO3 nanorods (Gd@WO3 NRs) were synthesized via facile hydrothermal method. The Gd@WO3 NRs were systematically characterized by XRD, RAMAN, FESEM, XPS, UV–Vis, ...and PL. XRD profiles confirmed the single phase of WO3, and the average crystallite size decreased with increasing the doping concentration. From EDS and XPS analysis of Gd@WO3 NRs, the presence of Gd, W, and O were confirmed without any additional peaks. UV–Vis spectra indicated that the position of the absorption edge lies within the visible region at all Gd contents in WO3, and the energy gap was studied. The photoluminescence test indicates that the 5 wt% of Gd doping in WO3 could reduce the photogenerated electron-hole pair recombination. The remarkable enhancement in the photodegradation activity for degrading the Rhodamine B under visible-light irradiation of WO3 was studied with Gd doping. The highest photocatalytic performance was found with 5 wt% Gd@WO3 NRs, due to the accelerated charge transfer process, which improved the photogenerated electron-hole pairs separation. According to trapping studies, the possible photocatalytic mechanism of Gd@WO3 NRs was also disclosed. The recycling test confirmed the stability of photocatalyst after three cycles. This novel Gd@WO3 NRs proved to be a superior catalyst for the reduction of organic pollutants.
This study investigates the potential of Al-decorated ZnO nanomaterials as a sensing material for detecting noxious nitrogen dioxide (NO2) gas. A series of samples with varying Al concentrations ...(0–6 mol%) were synthesized using a simple co-precipitation method. The structural, morphological, and spectral characteristics of the materials were thoroughly characterized using XRD, XPS, FESEM and EDX, HRTEM, BET, FTIR, and UV–Visible spectroscopy techniques. The prepared samples were investigated for the detection of NO2 gas at various concentrations (1–20 ppm) and at different operating temperatures (140°C–220 °C). Notably, the 2 mol% Al-decorated ZnO nanomaterial exhibited the highest NO2 gas sensing response, reaching a maximum value of 7.82 at 20 ppm concentration and 180 °C working temperature. The 2 mol% Al-decorated ZnO sensor demonstrated remarkable attributes, including rapid response and recovery times, consistent performance across a broad temperature range, excellent reproducibility, and stability. The study also investigated the mechanism underlying NO2 gas sensing by Al-decorated ZnO sensors and discussed the findings. The results of this study suggest that Al-decorated ZnO nanorods, particularly the 2 mol% Al-decorated ZnO sensor, have potential for NO2 gas detection in environmental monitoring and industrial applications.
•A range of sensors were synthesized, including pure ZnO and ZnO decorated-aluminium.•The 2 mol% Al-decorated sensor exhibited exceptional performance in detecting hazardous NO2 gas.•The study explored the sensing mechanism of Al-decorated ZnO sensors for NO2 gas, offering detailed analysis and discussion.
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•Preparation of the novel V2O5 nanorods array film sensor by one-step solvothermal route without any surfactant or template.•First in-situ deposition of the V2O5 nanorods array on ...ceramic tubes to form n-butylamine gas sensor.•V2O5 nanorods array film sensor exhibited faster response speed, higher sensing response and lower detection limit.
The regular and ordered arrangement of nanoarrays structure can provide effective transmission channels for the adsorption and desorption of gas molecules, and its excellent stability makes it have great advantages as a gas sensing material, which also poses challenges for the preparation of materials. In this work, V2O5 nanorods array was grown in-situ on ceramic tubes without seed layers by means of one-step solvothermal method. The structural characterization showed that the V2O5 nanorods array structure completely covered the surface of the ceramic tube. The gas sensing test results showed that the V2O5 nanorods array sensor had high response (100 ppm, Ra/Rg = 10.8), low detection limit (100 ppb), good reproducibility and long-term stability to n-butylamine. Its excellent sensing performance can be conributed to the fact that the array structure of nanorods can provide more active surfaces, and a great deal of gaps are formed between stacked nanorods, which is helpful to rapid response and recovery of gases. Moreover, from the perspective of the array structure of V2O5 nanorods and the chemical oxidation–reduction process, the possible detection mechanism of n-butylamine by the sensor was also discussed. The excellent gas sensing performance has the latent application prospect in the detection of trace amine gases.
The conventional Haber‐Bosch process for industrial ammonia production from N2 and H2 is not only energy‐intensive but also releases a large amount of CO2. The electrocatalytic nitrogen reduction ...reaction (NRR) is regarded as a sustainable and environmentally‐benign alternative approach for NH3 production under ambient conditions. In this communication, it is reported that Fe2O3 nanorods act as an efficient electrocatalyst for the NRR. In 0.1 M Na2SO4, it attains a Faradic efficiency of 0.94 % and NH3 yield of 15.9 μg h−1 mg−1cat. at −0.8 V vs. reversible hydrogen electrode. Furthermore, this catalyst also shows good stability during electrolysis and recycling tests.
Iron rods: here, Fe2O3 nanorods are reported as an efficient non‐noble‐metal electrocatalyst for the nitrogen reduction reaction under ambient conditions. The nanorods efficiently catalyze N2 to NH3 in 0.1 M Na2SO4, achieving a Faradaic efficiency of 0.94 % with a NH3 yield of 15.9 μg h−1 mg−1cat. at a potential of −0.8 V vs. reversible hydrogen electrode.
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•α-MnO2 nanorods forest were prepared without any surfactants by DC reactive sputtering for the first time.•BET surface area of the α-MnO2 nanorods is 164.2m2g−1.•α-MnO2 exhibits ...specific capacitance of 346Fg−1.•α-MnO2 nanorods supercapacitor electrode delivered high energy density 38.92Whkg−1.
In this work, a facile and novel approach is presented to maintain stoichiometry, to achieve stable nanostructure and high surface area manganese oxide (α-MnO2). The synthesis of α-MnO2 nanorods forest has been carried out using reactive DC magnetron sputtering technique without use of surfactant/wet chemical procedure. The structural parameters, vibrational response and surface morphology of the α-MnO2 nanorods are characterized using X-ray diffraction (XRD), Raman spectroscopy, Fourier transform Infrared spectroscopy (FT-IR), X-ray Photoluminescence spectroscopy (XPS), Field emission scanning electron microscopy (FE-SEM), Transmission electron miscopy (TEM) and BET surface area. The α-MnO2 nanorods have smooth surface and uniform diameters. The high surface area with lower lattice energy of poly nano-crystalline structure is expected to enhance the utilization ratio of electrode materials and facile de-intercalation process. The Mn-O-Mn bonded, MnO6 octahedral based and the well-developed tetragonal α-MnO2 with (2×2) tunnel is obtained. The mesopores in α-MnO2 provide wide channels, which is extremely suitable to transport ions into micropores present in α-MnO2. The electrochemical measurements are performed using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charge-discharge (GCD) techniques. The MnO2 electrode exhibits high specific capacitance (346Fg−1 at 0.71Ag−1 in 1M aqueous Na2SO4) and good cycling stability (86.6% retention after 1500 cycles). The present approach opens a new avenue to design an efficient chemical reaction free nanorods.
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