1D Nanostructures Research Articles

Electrospun niobium oxide 1D nanostructures and their applications in textile industry wastewater treatment

Electrospun niobium oxide 1D nanostructures and their applications in textile industry wastewater treatment

Autocatalytic reduction-assisted synthesis of segmented porous PtTe nanochains for enhancing methanol oxidation reaction

Morphology engineering has been developed as one of the most widely used strategies for improving the performance of electrocatalysts. However, the harsh reaction conditions and cumbersome reaction steps during the nanomaterials synthesis still limit their industrial applications. Herein, one-dimensional (1D) novel-segmented PtTe porous nanochains (PNCs) were successfully synthesized by the template methods assisted by Pt autocatalytic reduction. The PtTe PNCs consist of consecutive mesoporous architectures that provide a large electrochemical surface area (ECSA) and abundant active sites to enhance methanol oxidation reaction (MOR). Furthermore, 1D nanostructure as a robust sustaining frame can maintain a high mass/charge transfer rate in a long-term durability test. After 2,000 cyclic voltammetry (CV) cycles, the ECSA value of PtTe PNCs remained as high as 44.47 m²·g_Pt^–1, which was much larger than that of commercial Pt/C (3.95 m²·g_Pt^–1). The high catalytic activity and durability of PtTe PNCs are also supported by CO stripping test and density functional theory calculation. This autocatalytic reduction-assisted synthesis provides new insights for designing efficient low-dimensional nanocatalysts.

Present and future of functionalized Cu current collectors for stabilizing lithium metal anodes

Li metal has been recognized as the most promising anode materials for next-generation high-energy-density batteries, however, the inherent issues of dendrite growth and huge volume fluctuations upon Li plating/stripping normally result in fast capacity fading and safety concerns. Functionalized Cu current collectors have so far exhibited significant regulatory effects on stabilizing Li metal anodes (LMAs), and hold a great practical potential owing to their easy fabrication, low-cost and good compatibility with the existing battery technology. In this review, a comprehensive overview of Cu-based current collectors, including planar modified Cu foil, 3D architectured Cu foil and nanostructured 3D Cu substrates, for Li metal batteries is provided. Particularly, the design principles and strategies of functionalized Cu current collectors associated with their functionalities in optimizing Li plating/stripping behaviors are discussed. Finally, the critical issues where there is incomplete understanding and the future research directions of Cu current collectors in practical LMAs are also prospected. This review may shed light on the critical understanding of current collector engineering for high-energy-density Li metal batteries.

TỔNG HỢP VẬT LIỆU NANO THẤP CHIỀU LÕI-VỎ MoS2\TiO2 ỨNG DỤNG TRONG XÚC TÁC ĐIỆN HÓA SINH KHÍ H2

In this report, we present the synthesis of low dimensional shell-core (2D\1D) nanostructures, in which the TiO2 nanorods (TNRs) as the core are covered by a continuous monolayer MoS2 (1L-MoS2) as the shell. The obtain 1L-MoS2\TNRs was directly grown on the conduct graphite foil without any transfer process, thus minimizing the charge transfer resistance from the electrode to the outer most working surface. For the first steps, the TiO2 seed layer was designed by the AF sputtering method, then the TNRs were grown by hydrothermal approach. Thereafter, the TNRs were conformally coated by a continuous monolayer MoS2 via a metal-organic chemical vapor deposition technique, resulting in 1L-MoS2\TNRs nanomaterial. The structural, vibrational, and morphological characteristics demonstrated that the samples are high crystallinity. Interestingly, the 1L-MoS2\TNRs showed highly efficient in electrochemical HER activity with the smallest onset overpotential of -140 mV vs RHE and a corresponding Tafel slope of 80 mV per decade, which were much lower compared to the pristine 1L-MoS2 and TNRs.

Activation of 2D MoS2 electrodes induced by high-rate lithiation processes

The energy storage processes of a 2D MoS 2 electrode evolve over cycling from battery (I) to pseudocapacitive (II) and to double layer capacitive (III) processes. Physical activation processes (1 and 2) are at the origin. • 2D MoS 2 nanosheets are synthesized by a scalable liquid-phase exfoliation method. • 2D MoS 2 film electrodes were produced by a scalable spray deposition technique. • Conversion processes of nanostructured 2D MoS 2 electrodes are reversible. • High-rate lithiation processes induced activation of 2D MoS 2 electrodes. • Activation induced a conversion-to-capacitive type electrode transformation. • Activated 2D MoS 2 electrodes have superior cycling stability and rate performance. MoS 2 is a highly promising material for application in lithium-ion battery anodes due to its high theoretical capacity and low cost. However, problems with a fast capacity decay over cycling, especially at the first cycles, and poor rate performance have deterred its practical implementation. Herein, electrodes comprised solely of few-layers 2D MoS 2 nanosheets have been manufactured by scalable liquid-phase exfoliation and spray deposition methods. The long-standing controversy questioning the reversibility of conversion processes of MoS 2 -based electrodes was addressed. Raman studies revealed that, in 2D MoS 2 electrodes, conversion processes are indeed reversible, where nanostructure played a key role. Cycling of the electrodes at high current rates revealed an intriguing phenomenon consisting of a continuously increasing capacity after ca. 100–200 cycles. This phenomenon was comprehensively addressed by a variety of electrochemical and microscopy methods that revealed underlying physical activation mechanisms that involved a range of profound electrode structural changes. Activation mechanisms delivered a capacitive electrode of a superior rate performance and cycling stability, as compared to the corresponding pristine electrodes, and to MoS 2 electrodes previously reported. Herein, we have devised a methodology to overcome the problem of cycling stability of 2D MoS 2 electrodes. Moreover, activation of electrodes constitutes a methodology that could be applied to enhance the energy storage performance of electrodes based on other 2D nanomaterials, or combinations thereof, strategically combining chemistries to engineer electrodes of superior energy storage properties.

Mesoscopic 2D molecular self-assembly on an insulator

Two-dimensional (2D) nanostructures and nanomaterials offer potential for a wide range of technological applications in electronics, optoelectronics, data storage, sensing and catalysis. On-surface molecular self-assembly—where organic molecules act as building blocks and where surfaces play the role of supporting templates—allows for the bottom-up synthesis of such 2D systems with tuneable atomically precise morphologies and tailored electronic properties. These self-assembly protocols are well established on metal surfaces, but remain limited on electronically gapped substrates (insulators, semiconductors). The latter are useful for preventing electronic coupling (that is, hybridization between molecular assembly and underlying surface) and for avoiding quenching of optical processes, necessary for prospective electronic and optoelectronic applications. In particular, molecular self-assembly on surfaces other than weakly interacting metals can be challenging due to substrate reactivity, defects and inhomogeneities, resulting in intricate energy landscapes that limit the growth kinetically and hampers the synthesis of large-area defect-free 2D systems. Here, we demonstrate the self-assembly of a 2D, atomically thin organic molecular film on a model wide bandgap 2D insulator, single-layer hexagonal boron nitride (hBN) on Cu(111). The molecular film consists of flat, aromatic 9,10-di-cyano-anthracene (DCA) molecules. Our low-temperature scanning tunnelling microscopy and spectroscopy measurements revealed mesoscopic (>100 × 100 nm2), topographically homogeneous crystalline molecular domains resulting from flat molecular adsorption and noncovalent in-plane cyano-ring bonding, with electronically decoupled molecular orbitals (MOs) lying within the hBN electronic gap. These MOs exhibit an energy level spatial modulation (∼300 meV) that follows the moiré work function variation of hBN on Cu(111). These findings pave the way for large-area, atomically precise, highly crystalline 2D organic (and metal-organic) nanomaterials on electronically functional wide bandgap insulators.

Promotion of photocatalytic hydrogen evolution induced by graphitic carbon nitride transformation from 2D flakes to 1D nanowires

In this contribution, a sustainable approach to fabricate one-dimensional (1D) graphitic carbon nitride (gCN) for photocatalytic hydrogen generation is reported. The strategy was based on L-ascorbic acid (LAA) modification of two-dimensional (2D) gCN leading to the formation of a 1D structure. The resultant gCN_1D exhibits an increased photocatalytic hydrogen generation rate of ∼18-fold and 4-fold with respect to 2D bulk-gCN and exfoliated gCN (ex-gCN), respectively. The photocatalytic mechanism of hydrogen evolution from water splitting was proposed based on a detailed physiochemical investigation of the catalyst prior and after the process. The enhanced photocatalytic H2 generation of the gCN_1D is achieved due to enhanced light harvesting, the better position of valance and conduction bands, higher porosity, faster transfer and charge separation of photogenerated carriers, and lower recombination rate resulting from 1D nanostructure. Additionally, promoted stability is assigned to the formation of an additional phase of the CN4O8 during the photocatalytic process.

Ion Irradiation Effects on Two-Dimensional MXene Ti2C for Applications in Extreme Conditions: Combined Ab Initio and Monte Carlo Simulations

As an emerging category of two-dimensional (2D) materials, transition metal carbides and/or nitrides (MXenes) have attracted considerable interest for various disciplines. They exhibit unique properties typical of both metals and ceramics, rendering significant potential for harsh conditions such as in outer space and nuclear systems. In this work, using Ti2C as a prototype probe, we investigate the ion irradiation effects by combining ab initio and Monte Carlo simulations. We first consider the structures and energetics of various atomic vacancies in Ti2C. Based on binary collision approximation, a Monte Carlo approach is developed to explore the defects induced by ion bombardment. Systematic Monte Carlo (MC) simulations of different incident ions (i.e., H, He, Li, Be, B, C, N, O, F, and Ne) and selected isotopes reveal that defects are formed via primary collision and in-plane recoils, and the number of displaced atoms decreases with incident energy and increases with the atomic number of incident ions. Interestingly, Ti atoms are much easier to be knocked out than C atoms, beneficial for selective etching for nanoelectronics. We show that Ti2C remains metallic with vacancies of large size, indicating the high irradiation tolerance of electrical conductivity. This work not only provides fundamental insights into the irradiation response of MXenes but also paves the way for future exploration and implementation of 2D nanostructures in extreme conditions, e.g., as coatings or structural materials for nuclear reactors.

Synthesis of 3D Porous Cu Nanostructures on Ag Thin Film Using Dynamic Hydrogen Bubble Template for Electrochemical Conversion of CO2 to Ethanol.

Cu-based nanomaterials have been widely considered to be promising electrocatalysts for the direct conversion of CO2 to high-value hydrocarbons. However, poor selectivity and slow kinetics have hindered the use of Cu-based catalysts for large-scale industrial applications. In this work, we report on a tunable Cu-based synthesis strategy using a dynamic hydrogen bubble template (DHBT) coupled with a sputtered Ag thin film for the electrochemical reduction of CO2 to ethanol. Remarkably, the introduction of Ag into the base of the three-dimensional (3D) Cu nanostructure induced changes in the CO2 reduction reaction (CO2RR) pathway, which resulted in the generation of ethanol with high Faradaic Efficiency (FE). This observation was further investigated through Tafel and electrochemical impedance spectroscopic analyses. The rational design of the electrocatalyst was shown to promote the spillover of formed CO intermediates from the Ag sites to the 3D porous Cu nanostructure for further reduction to C2 products. Finally, challenges toward the development of multi-metallic electrocatalysts for the direct catalysis of CO2 to hydrocarbons were elucidated, and future perspectives were highlighted.

Two-Dimensional Metal Nanostructures: From Theoretical Understanding to Experiment.

This paper reviews recent studies on the preparation of two-dimensional (2D) metal nanostructures, particularly nanosheets. As metal often exists in the high-symmetry crystal phase, such as face centered cubic structures, reducing the symmetry is often needed for the formation of low-dimensional nanostructures. Recent advances in characterization and theory allow for a deeper understanding of the formation of 2D nanostructures. This Review firstly describes the relevant theoretical framework to help the experimentalists understand chemical driving forces for the synthesis of 2D metal nanostructures, followed by examples on the shape control of different metals. Recent applications of 2D metal nanostructures, including catalysis, bioimaging, plasmonics, and sensing, are discussed. We end the Review with a summary and outlook of the challenges and opportunities in the design, synthesis, and application of 2D metal nanostructures.

Novel 2D sulfur-doped V2O5 flakes and their applications in photoelectrochemical water oxidation and high-performance energy storage supercapacitors

Development of high-performance energy storage devices with exceptional and consistent performance is of immense significance due to ecological concerns to meet the growing demands for high-performance energy conversion and storage. V2O5 materials have attracted particular attention for energy storage owing to their excellent Faradaic performance, several oxidation valences, inexpensive, ease of synthesis, and non-toxic, all of which make them favorable materials for both energy conversion and storage applications. In this investigation, an efforts has been made to synthesize the novel 2D S-doped V2O5 flakes via a facile hydrothermal procedure. The materials developed were utilized in photoelectrochemical (PEC) water oxidation as well as electrochemical energy storage supercapacitors. XRD analysis confirmed that V2O5 crystal structure is orthorhombic, and doping of the sulfur ions into V2O5 lattice, which has considerably narrowed the band gap from 2.17 eV to 2.02 eV. Nyquist plots revealed that the doped electrode showed reduced inner resistance (RS) and charge transmission resistance (RCT) compared to that of naked electrode. Density functional theory (DFT) calculations illustrate that sulfur-ion doping in the two-dimensional V2O5 monolayer remarkably enhances the electrical properties of the materials. Furthermore, the doping of S into the host matrix causes a positive influence on its structure, electrical conductivity and ion diffusion. Doped V2O5 2D flakes exhibited a specific capacitance of 749F/g at 1 A/g with excellent stability after 3000 cycles at 2.5 A/g compared to the undoped sample. Furthermore, 2D S-doped V2O5 flakes showed ∼ 4.7 folds improvement in photocurrent density and reduced charge resistance than the undoped sample, indicating that doped V2O5 has excellent photoelectrochemical (PEC) water oxidation properties. The fabricated 2D nanostructured materials can be the potential materials for constructing inexpensive and high-performance energy conversion (e.g., hydrogen production, green energy generation), and energy storage devices.

Recent Progress and Challenges in MXene-Based Phase Change Material for Solar and Thermal Energy Applications

Energy storage is becoming a critical issue due to the diminishing availability of fossil fuels and the intermittent nature of current renewable energy sources. As a result, thermal management (TM) and thermal energy systems have gained significant attention due to their crucial roles in various industries. Among the different TM materials, MXenes, a member of the transition metal carbide/nitride family, have emerged as a promising material due to their unique 2D nanostructure, changeable surface chemistry, high electrical/thermal conductivity, light absorptivity, and low infrared emissivity. This review outlines the synthesis methods of MXenes and their various features and applications in thermal management. These 2D materials exhibit outstanding optical and thermal properties, making them suitable for thermal energy generation and storage. The study also covers the potential applications of MXene in the desalination industry, hybrid photovoltaic thermal systems, solar energy storage, electronics, and other thermal management related industries. The findings suggest that MXene-based TM materials have remarkable features that significantly influence thermal energy storage and conversion and present opportunities for further research in efficiently using these materials.

Nanoscale three-dimensional fabrication based on mechanically guided assembly

The growing demand for complex three-dimensional (3D) micro-/nanostructures has inspired the development of the corresponding manufacturing techniques. Among these techniques, 3D fabrication based on mechanically guided assembly offers the advantages of broad material compatibility, high designability, and structural reversibility under strain but is not applicable for nanoscale device printing because of the bottleneck at nanofabrication and design technique. Herein, a configuration-designable nanoscale 3D fabrication is suggested through a robust nanotransfer methodology and design of substrate’s mechanical characteristics. Covalent bonding–based two-dimensional nanotransfer allowing for nanostructure printing on elastomer substrates is used to address fabrication problems, while the feasibility of configuration design through the modulation of substrate’s mechanical characteristics is examined using analytical calculations and numerical simulations, allowing printing of various 3D nanostructures. The printed nanostructures exhibit strain-independent electrical properties and are therefore used to fabricate stretchable H2 and NO2 sensors with high performances stable under external strains of 30%.

Thermal Transport Study in a Strained Carbon Nanotube and Graphene Junction Using Phonon Wavepacket Analysis

This study investigates single-mode phonon scattering from a junction structure consisting of a (6,6) single-walled carbon nanotube (SWCNT) and graphene, subject to mechanical deformation, using phonon wavepacket analysis. Results show that longitudinal acoustic (LA) and transverse acoustic (TA) phonons at low frequencies are transmitted more effectively through the SWCNT–graphene junction when the junction is deformed. As low-frequency phonons in LA and TA modes are major energy carriers, it is expected that thermal transport across the SWCNT–graphene junction will be more efficient when the junction is deformed. Interfacial thermal resistance across the SWCNT-graphene junction was calculated using reverse nonequilibrium molecular dynamics (RNEMD). The RNEMD results show that the interfacial thermal resistance decreases when the structure is elongated, deforming the junction between the SWCNT and graphene. However, there was no notable difference in the transmission of twisting (TW) and flexural (FO) phonons when the junction was deformed. The study also showed that the transmission of phonon energy through the SWCNT–graphene junction has a slight dependence on the group velocity of phonons, with phonons having higher group velocities transmitting the junction more effectively. The findings of this research will play a significant role in advancing the development of futuristic electronics by providing a tool for developing 3D carbon nanostructures with high thermal performance under mechanical deformation.

1D Copper-based nanowire decorated with trimetallic nanoparticles affording abundant edges toward hydrogen generation in wide pH range

It still faces significant challenges in exploiting highly efficient and low-cost electrocatalysts for oxygen evolution reactions (OER) and hydrogen evolution reactions (HER) to boost the development of hydrogen energy. Herein, one-dimensional (1D) copper-based nanowires decorated with trimetallic nanoparticles on copper foam by in situ etching, forming PBA analogue and following low-temperature pyrolysis approach (Cu-Ru-PBA-H2/Ar). The specific 1D nanostructure decorated with numerous trimetallic nanoparticles can provide abundant active sites and favors mass transport during the electrocatalytic process. Moreover, the introduced Ru species and PBA analogue play pivotal roles in promoting catalytic performance. Then, the designed Cu-Ru-PBA-H2/Ar shows excellent all-pH HER performance with small overpotentials of 37, 34, and 89 mV in basic, neutral and acidic media, respectively, for providing 10 mA cm−2. This work provides a valuable way to exploit novel catalysts with hierarchical nanostructure in energy-related applications.

Defect-Engineering of 2D Dichalcogenide VSe2 to Enhance Ammonia Sensing: Acumens from DFT Calculations

Opportune sensing of ammonia (NH3) gas is industrially important for avoiding hazards. With the advent of nanostructured 2D materials, it is felt vital to miniaturize the detector architecture so as to attain more and more efficacy with simultaneous cost reduction. Adaptation of layered transition metal dichalcogenide as the host may be a potential answer to such challenges. The current study presents a theoretical in-depth analysis regarding improvement in efficient detection of NH3 using layered vanadium di-selenide (VSe2) with the introduction of point defects. The poor affinity between VSe2 and NH3 forbids the use of the former in the nano-sensing device's fabrications. The adsorption and electronic properties of VSe2 nanomaterials can be tuned with defect induction, which would modulate the sensing properties. The introduction of Se vacancy to pristine VSe2 was found to cause about an eight-fold increase (from -012 eV to -0.97 eV) in adsorption energy. A charge transfer from the N 2p orbital of NH3 to the V 3d orbital of VSe2 has been observed to cause appreciable NH3 detection by VSe2. In addition to that, the stability of the best-defected system has been confirmed through molecular dynamics simulation, and the possibility of repeated usability has been analyzed for calculating recovery time. Our theoretical results clearly indicate that Se-vacant layered VSe2 can be an efficient NH3 sensor if practically produced in the future. The presented results will thus potentially be useful for experimentalists in designing and developing VSe2-based NH3 sensors.

An electrochemical biosensor based on a highly loaded 3D DNA nanostructure for ultrasensitive detection of Pb2+

Herein, a novel three-dimensional (3D) DNA nanostructure with highly loaded capacity of methylene blue (MB) as signal molecule was constructed to fabricate an electrochemical biosensor for ultrasensitive detection of Pb2+. First, a small amount of target Pb2+ could be converted into numerous mimic targets D1, S1, D2 and S1′ with the assistant of Pb2+-dependent DNAzyme cleavage cycling, which could trigger MB labeled hairpin DNA H3, H4, H5 and H6 to undergo hybridization chain reaction (HCR) for forming layer A and layer B, respectively. Then, the proposed 3D DNA nanostructure was constructed by layer-by-layer assembly of the prepared layer A and layer B labeled with abundant MB for endowing the 3D DNA structure with excellent carrying capacity of MB and generating a remarkable electrochemical signal. Impressively, when the number of the assembly layers reached four, the optimal electrochemical signal value was obtained for achieving the ultrasensitive detection of Pb2+ with a low detection limit of 2.61 pM. Consequently, the proposed strategy provided a promising approach to design a novel 3D DNA structure with high loading capacity of signal molecule to construct high-performance sensor platform for ultrasensitive detection of biomarkers in diseases diagnosis and environmental monitoring.

Fabrication of superwetting non-woven fabric by grafting one-dimensional inorganic nanostructure for efficient separation of surfactant-stabilized organic solvent/water emulsions

The cobalt carbonate hydroxide one-dimensional (1D) needle-like nanostructure is grown on the non-woven fabric via hydrothermal method. The 1D interlaced needle-like structure not only reduces the pore size of the non-woven fabric but also provides rough micro-nano structure of the superhydrophilic cobalt carbonate hydroxide/non-woven fabric, which is endowed with superhydrophobicity by coating with polydimethylsiloxane (PDMS). The resulting superwetting non-woven fabrics exhibit high separation efficiency for a series of surfactant-stabilized organic solvent/water emulsions (more than 99.3% for both W/O and O/W emulsions) and preferable recyclability (more than 10 cycles). The fluxes for all W/O and O/W emulsions are above 300 L m−2 h−1. Meanwhile the superhydrophobic fabric exhibits outstanding chemical stability in acid, alkaline and salt solution, and good mechanical durability after abrasion test with sandpaper. The comprehensive performances of the superwetting fabrics based on 1D nanostructure make them possible to be promising material for the separation of organic solvent/water mixtures in polluted water in harsh environments.

Graphene Nanofoam Based Nanomaterials: Manufacturing and Technical Prospects

This article fundamentally reviews progress in the design and manufacturing of three-dimensional (3D) graphene-based nanocomposites for technical applications. The 3D graphene nanostructures have been manufactured using techniques like the template method, chemical vapor deposition, sol-gel, freeze-drying, hydrothermal technique, and other approaches. The nanofoam has been reinforced in polymers to achieve superior structural, morphological, and physical characteristics of the ensuing polymer/graphene nanofoam nanocomposites. The polymer/graphene nanofoam nanocomposites have been manufactured using the approaches like direct template method, in situ technique, infiltration process, and other methods. The 3D nanofoam- and polymer-based nanostructures have shown high specific surface area, suppleness, electron transport, thermal conduction, mechanical resilience, and other physical properties. The technical applications of hierarchical graphene nanofoams have been observed in the fields of radiation shielding, solar cells, supercapacitors, fuel cells, and other applications.

Ultrathin porous MnO2@C nanosheets for high-performance lithium-ion battery anodes

Engineering ultrathin porous two-dimensional (2D) MnO2/C composites is regarded as an efficient way to achieve high performance of MnO2 anode for lithium-ion batteries (LIBs) because of existence of many features such as shortened ion diffusion pathways and larger surface-controlled capacitance contribution, but they are difficult to prepare because of complex structures. Herein, we contribute a facile strategy for preparing ultrathin porous MnO2/C nanosheets and confirm that the introduced tetraethyl orthosilicate (TEOS) raw material plays a key role in formation of thus MnO2/C nanosheets. The as-prepared MnO2/C composite consists of ultrathin porous conformal carbon coated MnO2 nanosheets whereby integrates the advantages of 2D nanostructure, porous structure and superficial conformal carbon coating so as to improve lithium storage. As a result, this composite exhibits impressive performance, showing high capacity, long cycle life and improved rate capability, with 747.6 mA h g−1 after 400 cycles at 200 mA g−1 and 542.6 mA h g−1 after 420 cycles even at 1000 mA g−1. Based on systematic material and electrochemical characterizations we confirm that the outstanding performance of the as-prepared MnO2/C composite benefits from its well-designed nanostructure. Besides, we believe that this work can enlighten researchers to synthesize other 2D metal oxide/carbon composites for energy storage or other applications.