Nanobelt Arrays Research Articles

Co3O4 nanobelt arrays assembled with ultrathin nanosheets as highly efficient and stable electrocatalysts for the chlorine evolution reaction

We report Co3O4 nanobelt arrays (NBAs) assembled with ultrathin nanosheets prepared on fluorine doped tin oxide (FTO) substrates as electrocatalysts for the CER.

Vertically oriented TiS2−x nanobelt arrays as binder- and carbon-free intercalation electrodes for Li- and Na-based energy storage devices

Vertically-oriented TiS2 nanobelt arrays allow for the fabrication of carbon- and binder- free electrodes with high ion diffusion lengths.

N doped carbon coated V2O5 nanobelt arrays growing on carbon cloth toward enhanced performance cathodes for lithium ion batteries.

Highly flexible, binder-free cathodes for lithium ion batteries were fabricated by utilizing N doped carbon to coat V2O5 (V2O5@N-C) nanobelt arrays growing on carbon cloth. Such a robust architecture endows the electrode with effective ion diffusion and charge transport, resulting in high rate capability (135 mA h g−1 at 10C) and excellent cycling performance (215 mA h g−1 after 50 cycles at 0.5C).

Benzoate Anions-Intercalated Layered Nickel Hydroxide Nanobelts Array: An Earth-Abundant Electrocatalyst with Greatly Enhanced Oxygen Evolution Activity

The design and fabrication of earth-abundant and highly efficient water oxidation electrocatalysts are important for water splitting systems associated with the energy conversion and storage. In this work, we report an intercalation strategy to expand interlayer spacing of the layered structure and thus achieve great enhancement for water oxidation activity. Layered-structured nickel benzoate hydroxide nanobelts arrays on nickel foam (benzoate-Ni(OH)2/NF) are prepared by a one-step hydrothermal method. As-prepared benzoate-Ni(OH)2/NF exhibits outstanding oxygen evolution performance with the need of only 242 mV overpotential to drive a current density of 60 mA cm–2 in 1.0 M KOH, 126 mV lower than that for Ni(OH)2/NF. This catalyst electrode also has good stability with the maintenance of its catalytic activity for 27 h.

Benzoate Anion-Intercalated Layered Cobalt Hydroxide Nanoarray: An Efficient Electrocatalyst for the Oxygen Evolution Reaction.

Efficient oxygen evolution reaction (OER) catalysts are highly desired to improve the overall efficiency of electrochemical water splitting. We develop a benzoate anion-intercalated layered cobalt hydroxide nanobelt array on nickel foam (benzoate-Co(OH)2 /NF) through a one-pot hydrothermal process. As a 3 D electrode, benzoate-Co(OH)2 /NF with an expanded interlayer spacing (14.72 Å) drives a high OER catalytic current density of 50 mA cm-2 at an overpotential of 291 mV, outperforming its carbonate anion-intercalated counterpart with a lower interlayer spacing of 8.81 Å (337 mV overpotential at 50 mA cm-2 ). Moreover, this benzoate-Co(OH)2 /NF can maintain its catalytic activity for 21 h.

Three-dimensional Zn3V3O8/carbon fiber cloth composites as binder-free anode for lithium-ion batteries

Ternary metal vanadium oxides have been considered as potential anode materials for lithium-ion batteries (LIBs). However, the poor electronic conductivity and large volume expansion during the discharge/charge process lead to poor electrochemical performance. Herein, we firstly report the preparation of grass-like Zn3V3O8 nanobelts array coated 3D carbon fiber cloth (Zn3V3O8/CFC) as a binder-free anode for LIBs. The composites could effectively improve the kinetics of electronic transportation and mitigate the volume expansion of electrodes during discharge/charge process. As a result, the Zn3V3O8/CFC exhibits excellent Li+ storage properties. It can deliver a reversible capacity of ∼1750mAhg−1 at a low current density of 100mAg−1 and a specific capacity of 942mAhg−1 at the high rate of 1.5Ag−1. Even measured at high current density of 5Ag−1, the electrode could maintain a high capacity of 455mAhg−1 after 500 cycles with a capacity retention of 82.7%.

Angle-Dependent Photoluminescence Spectroscopy of Solution-Processed Organic Semiconducting Nanobelts

We report an anomalous anisotropy in photoluminescence (PL) from crystalline nanobelt of an organic small-molecule semiconductor, 6,13-dichloropentacene (DCP). Large-area well-aligned DCP nanobelt arrays are readily formed by self-assembly through solution method utilizing the strong anisotropic interactions between molecules. The absorption spectrum of the arrays suggests the formation of both intramolecular exciton and intermolecular exciton. However, the results of angle-dependent PL spectroscopy indicate that the PL arises only from the relaxation of intramolecular exciton, which has an optical transition dipole moment with an angle of 115° with the long-axis of the nanobelts. The angular dependence of PL signals follows a quartic rule (IPL(θ) ∝ cos4(θ – 115)) and agrees well with the optical selection rule of individual DCP molecules. The measured polarization ratio ρ from the individual nanobelts is on average 0.91 ± 0.02, superior to that of prior-art organic semiconductors. These results provide new insights into exciton behavior in 1D π–π stacking organic semiconductors and demonstrate DCP’s great potential in the photodetectors and optical switches for large-scale organic optoelectronics.

Growth of Fe2O3/SnO2 nanobelt arrays on iron foil for efficient photocatalytic degradation of methylene blue

Tin(IV) oxide has been intensively employed in optoelectronic devices due to its excellent electrical and optical properties. But the high recombination rates of the photogenerated electron-hole pairs of SnO2 nanomaterials often results in low photocatalytic efficiency. Herein, we proposed a facile route to prepare a novel Fe2O3/SnO2 heterojunction structure. The nanobelt arrays grown on iron foil naturally form a Schottky-type contact and provide a direct pathway for the photogenerated excitons. Hence, the Fe2O3/SnO2 nanobelt arrays exhibit much improved photocatalytic performance with the degradation rate constant on the Fe2O3/SnO2 film of approximately 12 times to that of α-Fe2O3 nanobelt arrays.

Enhanced electrochemical performance of orientated VO2(B) raft-like nanobelt arrays through direct lithiation for lithium ion batteries

Lithiation modification of VO2(B) has been carried out by a facile hydrothermal process, and the compact and locally ordered VO2(B) raft-like nanobelt arrays have been prepared. The synthesis route provides a new approach to elaborate a VO2(B) nanostructure under a mild environment condition. It is found that the growth mechanism of VO2(B) raft-like nanobelt arrays is different from the traditional nucleation-growth process. A novel chemical lithiating–exfoliating–splitting model is proposed. Compared with the bulk counterpart, the lithiated VO2(B) raft-like nanobelt arrays as cathodes exhibit a higher discharge capacity and an enhanced high-rate performance owing to their increased structural anisotropy and decreased polarization. This work indicates that VO2(B) raft-like nanobelt arrays have great potential applications as cathode materials for lithium ion batteries.

Substrate-dependent morphology and photoluminescence of MoS2 nanobelt arrays

As important two-dimensional nanostructures, MoS2 nanobelts grown on (AlGa)N and ZnO substrates, respectively, are facilely and economically fabricated by one-step chemical vapor deposition without using any catalyst. The characterizations for morphologies, compositions, and optical properties are performed by scanning electron microscopy (SEM), energy dispersed X-ray spectrometry (EDS), and photoluminescence spectroscopy (PL). SEM confirms that MoS2 nanobelts grown on (AlGa)N substrates compared with ones grown on ZnO substrates have higher quality although EDS shows that both of the nanobelt arrays are composed of the same constituents, that is, pure MoS2. In addition, the room-temperature optical properties show that MoS2 nanobelts on (AlGa)N substrates possess excellent photoluminescence superior to ones on ZnO substrates.

A cracking-assisted micro-/nanofluidic fabrication platform for silver nanobelt arrays and nanosensors.

Nanowires (NWs) with a high surface-to-volume ratio are advantageous for bio- or chemical sensor applications with high sensitivity, high selectivity, rapid response, and low power consumption. However, NWs are typically fabricated by combining several nanofabrication and even microfabrication processes, resulting in drawbacks such as high fabrication cost, extensive labor, and long processing time. Here, we show a novel NW fabrication platform based on "crack-photolithography" to produce a micro-/nanofluidic channel network. Solutions were loaded along the microchannel, while chemical synthesis was performed in the nanoslit-like nanochannels for fabricating silver nanobelts (AgNBs). In addition, the NW/NB fabrication platform not only made it possible to produce AgNBs in a repeatable, high-throughput, and low-cost manner but also allowed the simultaneous synthesis and alignment of AgNBs on a chip, eliminating the need for special micro- and/or nanofabrication equipment and dramatically reducing the processing time, labor, and cost. Finally, we demonstrated that the AgNBs can be used as chemical sensors, either as prepared or when integrated in a flexible substrate, to detect target analytes such as hydrogen peroxide.

V2O5 nanobelt arrays with controllable morphologies for enhanced performance supercapacitors

Controllable preparation of V2O5 nanobelt arrays as binder-free supercapacitive electrode materials and their charge–discharge mechanism.

Scalable single crystalline PMN-PT nanobelts sculpted from bulk for energy harvesting

Microelectromechanical systems (MEMS) incorporating piezoelectric elements enable highly sensitive sensors/actuators and effective energy harvesting. The development of a facile method for fabricating high-quality, deterministically positioned piezoelectric nanostructures provides new opportunities to build MEMS devices with dramatically higher performance. Piezoelectric materials with superior piezoelectric response, such as the relaxor ferroelectric Pb(Mg,Nb)O3-PbTiO3 (PMN-PT) represents a particularly interesting active material that functions as sensors/actuators and energy harvesters. Bottom-up synthesis of PMN-PT nanostructure suffers from polycrystallinity and stoichiometric deficiency. Yet, another main challenge is the deterministic positioning, aligning and integrating of as-synthesized nanostructures into functional arrays, in a similar manner to top-down strategies. Here, we fabricated scalable ordered single crystalline PMN-PT nanobelt (NB) arrays via a versatile top-down method. These NBs arrays, selectively sculpted from a single crystal bulk preserve well ferroelectric properties and exhibit the highest reported piezoelectric coefficient (~677pm/V). A flexible PMN-PT NB harvester was demonstrated based on these single crystalline NBs. The maximum output voltage and current reach ~6.0V and ~102μA, respectively under a 0.2% strain agitation. The result paves the way towards real application for top-down fabricated PMN-PT NBs as nanogenerators.

Best-Match Electrocatalysts from Homologous NixMy (M=O, S, P) Nanobelt Arrays in Overall Water Splitting

Homologous NiO, Ni3S2, and Ni2P nanobelt arrays grown on Ni foam were obtained by thermolysis, sulfuration and phosphorization of the same Ni(SO4)0.3OH1.4 belt-like precursors, respectively. Due to their 2D belt morphology and enhanced charge transport capability, they were used as efficient and stable non-noble metal electrocatalysts for water splitting. The influences of lengths and components of the catalysts on the catalytic performance were investigated. The NiO@Ni foam with reaction time of 6 hrs (NiO@NF-6) sample exhibits the overpotential of 0.42 V at 10 mA cm-2 in 1 mol L-1 KOH aqueous solution for oxygen evolution reaction (OER), lower than that of other prepared samples. The Ni2P@Ni foam with reaction time of 6 hrs (Ni2P@NF-6) sample displays the smallest overpotential of -99 mV at 10 mA cm-2 in 1 mol L-1 KOH aqueous solution for hydrogen evolution reaction (HER) of all the prepared samples. When the prepared arrays were deposited on the anode and cathode in a two-electrode setup for overall water splitting, the couple of NiO@NF-6/Ni2P@NF-6 needed only 1.67 V to afford the water splitting current of 10 mA cm-2 and the current density could maintain 95 % for 30 hrs in the long-term test carried out at 1.70 V in 1 mol L-1 KOH aqueous solution. It could be ascribed to the efficient charge transport between the belts and the conducting substrates, the accelerated surface reaction as their considerable specific surface area, and the promoted releasing of gas bubbles from the belt surfaces.

Substrate-free fabrication of self-supported V2O5 nanobelt arrays by a low-temperature solvothermal method with high electrochemical performance

In the designed synthesis, self-supported NH4V3O8 nanobelt arrays were prepared via a low-temperature solvothermal method. Then the NH4V3O8 nanobelt arrays were calcined in air atmosphere. Finally, a self-supported pattern of oriented V2O5 nanobelts was obtained for the first time. Further characterization methods certified that the growth direction of NH4V3O8 nanobelts was perpendicular to the orientation plane of self-formed NH4V3O8 sheet-like substrates. As a result, the nanobelts should stretch easily on the sheet-like substrate in an oriented manner. We prove that the solvent of ethanol plays a key role in the reaction and crystal growth process. It balances the two competing oxolation and olation reactions. Furthermore, the unique pattern served as high performance a lithium-ion battery and supercapacitor. Overall, the excellent electrochemical performances, for example, outstanding rate stability, remarkable cycling capacitance and ultrahigh capacity verify that the self-supported alignments have great potential applications in lithium-ion batteries and supercapacitors.

Synthesis of mesoporous niobium nitride nanobelt arrays and their capacitive properties

Mesoporous niobium nitride nanobelt arrays (Nb4N5 NBAs) are fabricated directly on Nb foils by a hydrothermal reaction in KOH, protonation treatment in HNO3, and calcination in an NH3 ambient. The morphology, composition and pore structure of the Nb4N5 NBAs are characterized in details. In addition, the mesoporous Nb4N5 NBAs electrode has good specific capacitance (37.4mFcm−2, or 124Fg−1) and delivers excellent rate performance due to the high porosity and good electron conductivity boding well for application to next-generation energy storage systems.

Facile synthesis of Ni-doped TiO2ultrathin nanobelt arrays with enhanced photocatalytic performance

Because of the high specific surface area and enhanced charge migration, TiO2 with unique belt-like nanostructures finds promising applications in various fields such as photocatalysis, dye-sensitized solar cells, gas sensors, and Li-ion batteries. In the current study, a solution combustion procedure was firstly adopted to prepare a black water-proof precursor. The black precursor interacted with H2O2 at ambient temperature, achieving a precursor solution that is capable of fabricating hydrogen titanate (H2Ti2O5·H2O) nanobelt arrays on metallic Ti substrates at 60 °C. Subsequent calcination in air at 400 °C achieved arrays of ultrathin anatase TiO2 nanobelts of ca. 2–4 nm in thickness. The addition of nickel nitrate in the combustion solution achieved the Ni-doping into the resultant TiO2 nanobelts, which did not alter the nanobelt structure but significantly reduced the band gap from 3.2 eV to 2.9 eV. When compared with the commonly alkali-hydrothermal synthesized anatase TiO2 nanobelts, the present ultrathin nanobelts exhibited much improved photocatalytic activity when utilized to assist photodegradation of rhodamine B in water. The ultrathin nanobelt structure is believed to contribute to the high specific surface area, the much reduced charge migration path, and the enhanced charge transport along the longitudinal direction. The appropriate Ni-doping further enhanced the photocatalytic performance, because of the increased light harvesting efficiency and reduced charge recombination.

Synthesis and enhanced photocatalytic activity of a BiOI/TiO2 nanobelt array for methyl orange degradation under visible light irradiation

A novel heterojunction by facet coupling of BiOI onto TiO2 nanobelt arrays (NBAs) as a visible light photocatalyst was achieved through a hydrothermal method.

Commercial Dacron cloth supported Cu(OH)2 nanobelt arrays for wearable supercapacitors

Commercial Dacron cloth is directly used as a substrate for the growth of Cu(OH)2 nanobelt arrays for application in flexible all-solid-state supercapacitors.

Gravity-Driven Multiple Collision-Enhanced Catalytic Soot Combustion over a Space-Open Array Catalyst Consisting of Ultrathin Ceria Nanobelts.

More than 122 times higher contact efficiency between soot and catalysts is achieved over the as-prepared CeO(2) nanobelt array catalysts as compared with the powder nanoparticle catalyst. A novel gravity-driven multiple collision-enhanced soot combustion mechanism is proposed for the first time.