Nanobelt Arrays Research Articles

Tuning architectural synergy reactivity of nano-tin oxide on high storage reversible capacity retention of ammonium vanadate nanobelt array cathode for lithium-ion battery

Enabling ambient cycling stability of vanadium-based materials is of fundamental importance in the advancement of next generation electrodes for high-performance lithium-ion batteries. Although, extending these host layered nano-architectures illustrate the effective electrochemical activity by regulating the gallery space for fast Li+ storage, the reported structural integrity in terms of the cycling stability for vanadium-based cathodes is highly challenging. In present study, a series of NH4V4O10-SnO2 (NHV-SnO2) nanocomposite consisting of diverse contents of SnO2 (x: 5.0, 15.0 and 30.0 wt%) were synthesized through a three-step program based on sonochemical-calcination-hydrothermal treatment and employed as an advanced energetic material for lithium-ion battery cathodes. For the first time, understanding the impact of SnO2 loading on electrochemical reactions of NHV-based electrodes was regarded as an effective engineering strategy to optimize structural modulation and cell lifetime without distinct capacity fading. Notably, combination of NHV and SnO2 in optimum proportions not only enhances the specific surface area, but also expand buffer the volume change for lithium-ion intercalation/extraction. By this design, the assembled battery containing 15.0 wt% SnO2 illustrated stable capacities of 301.77 mAh g−1 (30 mA g−1) and 232.05 mAh g−1 (240 mA g−1) with capacity retention values as high as 97.94 % and 97.03 % for 50 cycles, respectively. Of note, the results described here could show a vital guidance toward designing better composite-based cathode material for energy storage devices.

Eco‐friendly Visible Wavelength Photodetectors Based on Colloidal Molybdenum Trioxide Nanobelt Arrays

AbstractIn an era marked by a growing emphasis on sustainability and innovation, the quest for eco‐friendly solutions to energy conversion devices capable of harnessing visible light has gained paramount importance. In response to this critical demand, we demonstrate visible light‐responsive photoswitching from molybdenum trioxide nanobelt arrays in the photoconductive device fabricated using solution‐processing technique. We exploit the visible light‐driven modulation of conductivity in the reversibly switchable photochromic state of MoO3 to develop a photochromism‐assisted photoconductive photodetector with fast response (<0.1 s), significant photocurrent on/off ratio and excellent responsivity (41 AW−1 at 459 nm) under the applied bias of 5 V. The light harvesting strategy presented herein holds the potential for efficient energy generation by harnessing visible light, even under low‐light conditions.

(Invited) Research Progress of Electrocatalyst and MEA of PEM Fuel Cell and Water Electrolyser

The successful commercialization of PEM fuel cell and water electrolyser is determined by the performance, durability, and cost of electrocatalyst and MEA. Compared with conventional electrodes, nanoarray electrodes feature enhanced mass transport thanks to continuous proton and electron transport channels. Herein, a series of nanoarray electrodes were developed directly as the electrodes for PEM fuel cells and water electrolysers. A catalyst layer based on porous Pt−Ni nanobelt arrays were prepared by the magnetron sputtering of Pt and Ni on a sacrificed template, followed by acid etching. The porous Pt−Ni nanobelt arrays-based catalyst layer exhibited superior fuel cell performance in H2/air conditions and RH 40%. The performance of the MEA with porous Pt−Ni nanobelt arrays reached 366.6 and 597.6 mW cm−2 with Pt loadings of 36.5 μg cm−2/36.5 μg cm−2 and 108.9 μg cm−2/108.9 μg cm−2 at the cathode/anode, respectively. Besides, a WO3 nanoarray electrode with a heterogeneous IrRu coating was prepared via a facile electrodeposition approach. The obtained IrRu@WO3 electrode exhibits a competitive overpotential of 245 mV at 10 mA cm−2. A single cell enables a current density of 4.5 A cm−2 at 2.13 V with the Ir loading of 115 mg cm−2. The nanoarray structure remains unchanged in a single-cell during a 500-h stability test. In sum, these work highlights a new approach to enhance the performance and durability for PEM fuel cells and water electrolysers.

Numerous active sites in self-supporting Co3O4 nanobelt array for boosted and stabilized 5-hydroxymethylfurfural electro-oxidation

Constructing an efficient electrocatalyst for the oxidation of 5-Hydroxymethylfurfural (HMF) to 2,5-furan dicarboxylic acid (FDCA) is highly desirable in achieving biomass conversion. Generally, there are two strategies to enhance the electrocatalyst’s activity: increasing the number of active site or increasing the intrinsic activity of each active site. Compared with the latter, the former is usually ignored in the HMF oxidation reaction (HMFOR), but it is very critical for practical applications. Herein, we fabricate a self-supporting three-dimensional porous Co3O4 nanobelt array decorated on nickel foam (P-Co3O4-NBA@NF) electrode with numerous active sites. Benefiting from the unique structural feature, P-Co3O4-NBA@NF electrode demonstrates nearly 100% of HMF conversion efficiency, 96.9% of FDCA selectivity, and 97.0% of Faraday efficiency. Notably, it can also deliver remarkable long-term stability over 30 continuous cycles. These exceptional features position P-Co3O4-NBA@NF as one of the promising electrocatalysts reported thus far for HMFOR.

Preparation of V2O5 nanobelt arrays/NiO nanosheet arrays composite as supercapacitor electrode material

V2O5 nanobelt arrays (VNBAs) is fabricated on Ni foam by using an easy hydrothermal route and then NiO nanosheet arrays (NNSAs) is grown on VNBAs by using a simple chemical bath deposition approach to form VNBAs/NNSAs composite. It is found that the monocrystalline VNBAs with a lamellar structure is uniformly distributed on nickel foam and the polystalline NNSAs with a close packed structure is closely covered on the VNBAs. CV, GCD, EIS and CA electrochemical techniques are used to test the supercapacitive properties of the VNBAs/NNSAs composite. The single electrode displays a high specific capacity of 875 F g−1, a good cycling stability of 96.1%, a small charge transfer resistance of 1.32 Ω and a rapid ion diffusivity of 2.5 × 10−8 cm2 s−1. The symmetric supercapacitor combined by the VNBAs/NNSAs displays a large energy density of 120.1 W h kg−1 at 400 W kg−1 and it retains 68.3 W h kg−1 at 8000 W kg−1. The VNBAs/NNSAs composite with high electrochemical performance is a potential supercapacitor electrode material.

Ultrafine Pt NanoparticlesAnchored on 2D Metal-Organic Frameworks as Multifunctional Electrocatalysts for Water Electrolysis and Zinc-Air Batteries.

Multifunctional electrocatalysts are crucial to cost-effective electrochemical energy conversion and storage systems requiring mutual enhancement of disparate reactions. Embedding noble metal nanoparticles in 2D metal-organic frameworks (MOFs) are proposed as an effective strategy, however, the hybrids usually suffer from poor electrochemical performance and electrical conductivity in operating conditions. Herein, ultrafine Pt nanoparticles strongly anchored on thiophenedicarboxylate acid based 2D Fe-MOF nanobelt arrays (Pt@Fe-MOF) are fabricated, allowing sufficient exposure of active sites with superior trifunctional electrocatalytic activity for hydrogen evolution, oxygen evolution, and oxygen reduction reactions. The interfacial Fe─O─Pt bonds can induce the charge redistribution of metal centers, leading to the optimization of adsorption energy for reaction intermediates, while the dispersibility of ultrafine Pt nanoparticles contributes to the high mass activity. When Pt@Fe-MOF is used as bifunctional catalysts for water-splitting, a low voltage of 1.65V is required at 100mA cm-2 with long-term stability for 20h at temperatures (65°C) relevant for industrial applications, outperforming commercial benchmarks. Furthermore, liquid Zn-air batteries with Pt@Fe-MOF in cathodes deliver high open-circuit voltages (1.397V) and decent cycling stability, which motivates the fabrication of flexible quasisolid-state rechargeable Zn-air batteries with remarkable performance.

Reversible active bridging sulfur sites grafted on Ni3S2 nanobelt arrays for efficient hydrogen evolution reaction

Elaborate and rational design of cost-effective and high-efficiency non-noble metal electrocatalysts for pushing forward the sustainable hydrogen fuel production is of great significance. Herein, a novel VS4 nanoparticle decorated Ni3S2 nanobelt array in-situ grown on nickel foam (VS4/Ni3S2/NF NBs) was prepared by a self-templated synthesis strategy. Benefitting from the unique nanobelt array structure, abundant highly active bridge S22- sites and strong electronic interaction between VS4 and Ni3S2 on the heterointerface, the integrated VS4/Ni3S2/NF NBs exhibited excellent electrocatalytic hydrogen evolution activity and robust stability. The density functional theory (DFT) further revealed the reversible conversion catalysis mechanism of bridging S22- sites in VS4/Ni3S2/NF NBs during HER process. Notably, bidentate bridging SS bonds as the predominant catalytically active centers can spontaneously open once H adsorbed its surface, leading to the aggregation of negative charges on S atoms and thus facilitating the generation of H* intermediates, and spontaneously close when H* desorption is going to form H2. Our work provides fresh insights for developing potential polysulfides as high-performance hydrogen-evolving electrocatalysts for prospective clean energy production from water splitting.

Controllable preparation and photoelectric properties of oriented two-dimensional GeSe2 nanobelt arrays

Germanium diselenide (GeSe2) nanobelts are synthesized by atmospheric-pressure chemical vapor deposition under low temperature by using Se and Ge powders as precursor materials in a quartz tube furnace with double heating zones. The GeSe2 nanobelts thus prepared exhibit growth directionality. Unidirectional nanobelt clusters are tightly spaced and shaped as rectangular nanobelt arrays. Additionally, the thickness of the prepared GeSe2 material is less than 5 nm, and the area of a single array can attain 0.96 mm2. Our experimental results show that hydrogen directly affects the growth of GeSe2. First-principles calculations reveal the electronic properties and in-plane anisotropic optical absorption of the few-layer two-dimensional GeSe2 material. Optical absorbance measurements of GeSe2 nanobelt arrays reveal high ultraviolet absorbance of GeSe2 (200–400 nm). Photodetectors based on GeSe2 nanobelts are p-type, with high responsivity, superior detectivity, and a fast response time. These results show that GeSe2 is an excellent ultraviolet photoelectric material with potential photoelectronic applications.

Synthesis of Co(OH)F@Al nanobelt array on various substrates for pyro-MEMS

Metastable intermolecular composites (MICs) composed by solid fuel and oxidizer can undergo violent redox reaction with release of huge amount of energy. Integration of MIC with microelectromechanical-system (MEMS) is of particular interest to meet the demand of miniaturization in modern pyrotechnic devices. Meanwhile, fluorine-containing oxidizers are favored in MIC owing to their potential to fluorinate the oxide passivation layer in common elemental fuels. Herein, Co(OH)F was employed for the first time as a novel fluorine-containing oxidizer in Al-based MIC. Vertically aligned Co(OH)F@Al nanobelt arrays (NAs) with tunable morphology were successfully fabricated on a variety of substrates (Si, glass, Ni, Cu, Ti) via a facile hydrothermal synthesis followed by electron beam evaporation. The whole fabrication process is highly compatible with modern MEMS technology. The thermal behavior of pure Co(OH)F and Co(OH)F@Al composites was comprehensively investigated by TG-DSC and a series of ex-situ and in-situ characterization. It was found that, Co(OH)F@Al composites achieved main exothermal reaction before melting of Al regardless of morphology and equivalence ratio. This feature is attributed to the etching of Al2O3 shell by HF released from Co(OH)F which is termed as pre-ignition reaction. To elucidate the effect of micro-structure on the actual specific heat release, we proposed a phenomenological model which can be a reference for future micro-structure design of MIC.

Constructing Co@TiO2 Nanoarray Heterostructure with Schottky Contact for Selective Electrocatalytic Nitrate Reduction to Ammonia.

Electrochemical nitrate (NO3 - ) reduction reaction (NO3 - RR) is a potential sustainable route for large-scale ambient ammonia (NH3 ) synthesis and regulating the nitrogen cycle. However, as this reaction involves multi-electron transfer steps, it urgently needs efficient electrocatalysts on promoting NH3 selectivity. Herein, a rational design of Co nanoparticles anchored on TiO2 nanobelt array on titanium plate (Co@TiO2 /TP) is presented as a high-efficiency electrocatalyst for NO3 - RR. Density theory calculations demonstrate that the constructed Schottky heterostructures coupling metallic Co with semiconductor TiO2 develop a built-in electric field, which can accelerate the rate determining step and facilitate NO3 - adsorption, ensuring the selective conversion to NH3 . Expectantly, the Co@TiO2 /TP electrocatalyst attains an excellent Faradaic efficiency of 96.7% and a high NH3 yield of 800.0µmolh-1 cm-2 under neutral solution. More importantly, Co@TiO2 /TP heterostructure catalyst also presents a remarkable stability in 50-h electrolysis test.

High-efficiency electroreduction of nitrite to ammonia on a Cu@TiO2 nanobelt array.

Electrochemical nitrite (NO2-) reduction is a potential and sustainable route to produce high-value ammonia (NH3), but it requires highly active electrocatalysts. Herein, Cu nanoparticles anchored on a TiO2 nanobelt array on a titanium plate (Cu@TiO2/TP) are reported as a high-efficiency electrocatalyst for NO2--to-NH3 conversion. The designed Cu@TiO2/TP catalyst exhibits outstanding catalytic performance toward the NO2-RR, with a high NH3 yield of 760.5 μmol h-1 cm-2 (237.7 μmol h-1 mgcat.-1) and an excellent faradaic efficiency of 95.3% in neutral solution. Meanwhile, it also presents strong electrochemical stability during cyclic tests and long-term electrolysis.

Unveiling selective nitrate reduction to ammonia with Co3O4 nanosheets/TiO2 nanobelt heterostructure catalyst.

Electrochemical nitrate (NO3-) reduction reaction (NO3RR) possesses two-pronged properties for sustainable ammonia (NH3) synthesis and mitigating NO3- contamination in water. However, the sluggish kinetics for the direct eight-electron NO3--to-NH3 conversion makes a formidable challenge to develop efficient electrocatalysts. Herein, we report a heterostructure of Co3O4 nanosheets decorated TiO2 nanobelt array on titanium plate (Co3O4@TiO2/TP) as an efficient NO3RR electrocatalyst. Both experimental and density theory calculations reveal that the heterostructure of Co3O4@TiO2 establishes a built-in electric field which can optimize the electron migration kinetics, as well as facilitate the adsorption and fixation of NO3- on the electrode surface, ensuring the selectivity to NH3. As expected, the designed Co3O4@TiO2/TP exhibits a remarkable Faradaic efficiency of 93.1% and a remarkable NH3 yield as high as 875μmolh-1 cm-2, superior to Co3O4/TP and TiO2/TP. Significantly, it also demonstrates strong electrochemical durability.

V-doped TiO2 nanobelt array for high-efficiency electrocatalytic nitrite reduction to ammonia

Electrocatalytic nitrite (NO2−) reduction to ammonia (NH3) has been an attractive topic, which not only removes NO2− pollutants existing in surface water and underground water but also synthesizes value-added NH3. Nevertheless, the inactive kinetics for direct six-electron NO2−-to-NH3 conversion makes it challenging to explore efficient electrocatalysts for the NO2− reduction reaction (NO2RR). Herein, we report a V-doped TiO2 nanobelt array on a titanium plate (V–TiO2/TP) as a highly efficient NO2RR electrocatalyst. The experimental results and theoretical calculations clarify that V doping can enhance the intrinsic electrical conductivity and effectively optimize the free energy of the TiO2 (101) crystal plane in the potential determining step, resulting in a positive effect on electrochemical NO2RR to NH3. The designed V–TiO2/TP exhibits an outstanding electrochemical NO2RR property with a high NH3 yield of 540.8 μmol h−1 cm−2 at −0.7 V and an excellent Faradaic efficiency of 93.2% at −0.6 V versus reversible hydrogen electrode, superior to TiO2/TP.

In-Situ and controllable construction of Mo2N embedded Mo2C nanobelts as robust electrocatalyst for superior pH-universal hydrogen evolution reaction

The development of high active and cost-effective transition metal based catalysts as alternatives to Pt-based electrocatalysts for pH-universal hydrogen evolution reaction (HER) is highly desirable. Herein, we proposed a novel strategy to construct Mo2N uniformly embedded Mo2C nanobelt arrays electrocatalyst on N doped carbon framework (Mo2N-Mo2C/NC NBAs) by nitridation of MoOx/C hybrid precursors and subsequent annealing. The effect of N content towards the composition ratio of Mo2N to Mo2C and the structural evolution were studied. The in-situ formed Mo2N reduces the sintering of Mo2C phase and creates amounts of compact Mo2N-Mo2C interfaces and mesopores. Because of these high active interfaces, mesopores structure and self-supported architecture, the resultant Mo2N-Mo2C/NC catalyst exhibits remarkable HER performance and durability over a wide pH range, as exemplified by a small overpotentials of 75, 93, and 114 mV at 10 mA cm−2, and Tafel slopes of 43, 58, and 62 mV dec−1 in the alkaline, neutral and acidic media. The results reveal a new avenue to design highly efficient electrocatalysts with tailored hetero/microstructures, which could be extended to fabricate other high-performance electrocatalyst and electrode materials for electrochemical energy conversion.

Triboelectric nanogenerator based on flexible Janus nanofiber membrane with simultaneous high charge generation and charge capturing abilities

Triboelectric nanogenerator (TENG) based on nanomaterials has broad application values in flexible wearable devices. Here, a new-typed TENG-JNM based on a flexible two-dimensional (2D) Janus nanofiber membrane (JNM) and PMMA nanobelt array is assembled, where JNM and PMMA nanobelt array are respectively constructed by special electrospun one-dimensional (1D) [CNTs/PVDF/PVP]//[Eu(TTA)3(TPPO)2/PVDF/PVP] Janus nanofiber and PMMA nanobelt as building units. Different functional substances are pre-assembled into Janus nanofiber utilizing structural asymmetry, so charge generation and charge capturing abilities are pre-realized in microscopic 1D Janus nanofiber, which further makes 2D JNM concurrently act as charge generation and charge capturing layers of TENG-JNM without introducing usually-adopted additional macroscopic charge capturing layer. Two independent domains are gained in Janus nanofiber and different functional substances are limited in their own domains, effectively weakening harmful mutual interferences. JNM displays improved charge generation ability by introducing CNTs and Eu(TTA)3(TPPO)2 and high charge capturing ability by utilizing the two-phase interfaces between Eu(TTA)3(TPPO)2 and PVDF matrix to timely capture triboelectric charges to avoid adverse combination with induced charges and charge dissipation. PMMA nanobelt array with compact and smooth surface is also conducive to acquiring adequate contact area between PMMA nanobelt array and JNM. TENG-JNM gains high and adjustable output performance, in which the maximum output performance is 22.4 μA, 353.5 V and 135.5 μC·m−2. TENG-JNM is endowed with excellent red fluorescence, realizing the visualization of working state in dark environment. TENG-JNM has potential application values in electronic skin or wearable devices.

Liquid-Phase van der Waals Epitaxy of a Few-Layer and Unit-Cell Thick Ruddlesden-Popper Halide Perovskite.

2D Ruddlesden-Popper (RP) halide perovskites with natural multiple quantum well structures are an ideal platform to integrate into vertical heterostructures, which may introduce plentiful intriguing optoelectronic properties that are not accessible in a single bulk crystal. Here, we report liquid-phase van der Waals epitaxy of a 2D RP hybrid perovskite (4,4-DFPD)2PbI4 (4,4-DFPD is 4,4-difluoropiperidinium) on muscovite mica and fabricate a series of perovskite-perovskite vertical heterostructures by integrating it with a second 2D RP perovskite R-NPB [NPB = 1-(1-naphthyl)ethylammonium lead bromide] sheets. The grown (4,4-DFPD)2PbI4 nanobelt array can be multiple layers to unit-cell thin and are crystallographically aligned on the mica substrate. An interlayer photo emission in this R-NPB/(4,4-DFPD)2PbI4 heterostructure with a lifetime of about 25 ns at 120 K has been revealed. Our demonstration of epitaxial (4,4-DFPD)2PbI4 array grown on mica via liquid-phase van der Waals epitaxy provides a paradigm to prepare orderly distributed 2D RP hybrid perovskites for further integration into multiple heterostructures. The discovery of a new interlayer emission in the R-NPB/(4,4-DFPD)2PbI4 heterostructure enriches the basic understanding of interlayer charge transition in halide perovskite systems.

Boosting Charge Transfer Via Heterostructure Engineering of Ti2CTx/Na2Ti3O7 Nanobelts Array for Superior Sodium Storage Performance

The poor conductivity, inert charge transmission efficiency, and irreversible Na+ trapping of Na2 Ti3 O7 result in retardant electrons/ions transportation and deficient sodium-ion storage efficiency, leading to sluggish reaction kinetics. To address these issues, an urchin-like Ti2 CTx /Na2 Ti3 O7 (Ti2 C/NTO) heterostructure sphere consisting of Ti2 C/NTO heterostructure nanobelts array is developed via a facile one-step in situ hydrothermal strategy. The Ti2 C/NTO heterostructure can obviously decrease Na+ diffusion barriers and increase electronic conductivity to improve reaction kinetics due to the built-in electric field effect and high-quantity interface region. In addition, the urchin-like vertically aligned nanobelts can reduce the diffusion distance of electrons and ions, provide favored electrolyte infiltration, adapt large volume expansion, and mitigate the aggregation to maintain structural stability during cycles, further enhancing the reaction kinetics. Furthermore, the Ti2 C/NTO heterostructure can effectively suppress many unwanted side reactions between reactive surface sites of NTO and electrolyte as well as irreversible trapping of Na+ . As a result, systematic electrochemical investigations demonstrate that the Ti2 C/NTO heterostructure as an anode material for record sodium-ion storage delivers the highest reversible capacity, the best cycling stability with 0.0065% decay rate for 4500 cycles at 2.0 A g-1 , and excellent rate capability of 172.1 mAh g-1 at 10.0 A g-1 .

High-Efficiency Ammonia Electrosynthesis on Anatase TiO2-x Nanobelt Arrays with Oxygen Vacancies by Selective Reduction of Nitrite.

Electrocatalytic reduction of nitrite to NH3 provides a new route for the treatment of nitrite in wastewater, as well as an attractive alternative to NH3 synthesis. Here, we report that an oxygen vacancy-rich TiO2-x nanoarray with different crystal structures self-supported on the Ti plate can be prepared by hydrothermal synthesis and by subsequently annealing it in an Ar/H2 atmosphere. Anatase TiO2-x (A-TiO2-x) can be a superb catalyst for the efficient conversion of NO2- to NH3; a high NH3 yield of 12,230.1 ± 406.9 μg h-1 cm-2 along with a Faradaic efficiency of 91.1 ± 5.5% can be achieved in a 0.1 M NaOH solution containing 0.1 M NaNO2 at -0.8 V, which also exhibits preferable durability with almost no decay of catalytic performances after cycling tests and long-term electrolysis. Furthermore, a Zn-NO2- battery with such A-TiO2-x as a cathode delivers a power density of 2.38 mW cm-2 as well as a NH3 yield of 885 μg h-1 cm-2.

KTi8O16.5 Nanobelt Array with the Zero Strain Property for High-Performance Lithium-Ion Batteries with Enhanced Capacity and Rate Capability

KTi₈O_16.5 Nanobelt Array with the Zero Strain Property for High-Performance Lithium-Ion Batteries with Enhanced Capacity and Rate Capability

Facile construction of porous and heterostructured molybdenum nitride/carbide nanobelt arrays for large current hydrogen evolution reaction

The development of cost-effective, highly efficient and stable electrocatalysts for alkaline water electrolysis at a large current density has attracted considerable attention. Herein, we reported a one-dimensional (1D) porous Mo2C/Mo2N heterostructured electrocatalyst on carbon cloth as robust electrode for large current hydrogen evolution reaction (HER). The MoO3 nanobelt arrays and urea were used as the metal and non-metal sources to fabricate the electrocatalyst by one-step thermal reaction. Due to the in-situ formed abundant high active interfaces and porous structure, the Mo2C/Mo2N electrocatalyst shows enhanced HER activity and kinetics, as exemplified by low overpotentials of 54, 73, and 96 mV at a current density of 10 mA cm−2 and small Tafel slopes of 48, 59 and 60 mV dec−1 in alkaline, neutral and acid media, respectively. Furthermore, the optimal Mo2C/Mo2N catalyst only requires a low overpotential of 290 mV to reach a large current density of 500 mA cm−2 in alkaline media, which is superior to commercial Pt/C catalyst (368 mV) and better than those of recently reported Mo-based electrocatalysts. This work paves a facile strategy to construct highly efficient and low-cost electrocatalyst for water splitting, which could be extended to fabricate other heterostructured electrocatalyst for electrocatalysis and energy conversion.