Interplanar Space Research Articles

A Sweet Synthesis of MXenes.

Two-dimensional transition metal carbides/nitrides (MXenes) have shown great promise in various applications. However, mass production of MXenes suffers from the excessive use of toxic fluorine-containing reagents. Herein, a new method was validated for synthesizing MXenes from five MAX ceramics. The method features a minimized (stoichiometric) dosage of F-containing reagent (NaBF4) and polyols (glycerol, erythritol, and xylitol) as the reaction solvent. Due to the sweetness of polyols and the low environmental impact, we refer to this method as a "sweet" synthesis of MXenes. An in-depth molecular dynamics simulation study, combined with experimental kinetic parameters, further revealed that the diffusion of F- in the confined interplanar space is rate-determining for the etching reaction. The expansion of interlayer spacing by polyols effectively reduces the diffusion activation energy of F- and accelerates the etching reaction.

A comparative approach for estimating microstructural characteristics of BaTi1−xZrxO3 (0.0 ≤ x ≤ 0.3) nanoparticles via X-ray diffraction patterns

Barium titanate materials are currently a special topic for scientific research due to their effective technological applications. The tetragonal BaTi1-xZrxO3 (0.0 ≤ x ≤ 0.3) nanoparticles (NPs) were synthesized using a modified citrate technique. The current work provides a comparative approach for the calculation of crystallite size, stress, strain, and elastic characteristics based on X-ray diffraction (XRD) patterns. Various models have been developed to analyze XRD data; these models differ in their assumptions, mathematical approaches, and the type of information they provide. The Scherrer model ignores lattice micro-structures that develop in nanostructures, such as intrinsic strain. To overcome such drawbacks, three Williamson-Hall models, (the uniform deformation model (UDM)), the uniform stress deformation model (USDM), and the uniform deformation energy density model (UDEDM) have been discussed. According to the USDM model, with increasing Zr ion concentrations, interplanar space increases, causing a drop in Young’s modulus. All the previous approaches take into account the diffraction angle (2θ)-dependent peak broadening, which is thought to represent a combination of size and strain-driven induced broadening.Graphical

Enhancing Interplanar Spacing in V2O3/V3O7 Heterostructures to Optimize Cathode Efficiency for Zn-Ion Batteries.

The improvement of sophisticated cathode materials plays a major role in boosting the efficiency of Zn-ion batteries. These batteries have garnered considerable interest as a result of their excellent energy density and the promise of cost-effective solutions for energy storage. In this work, we present a novel approach to progress the electrochemical investigation of Zn-ion batteries by expanding the interplanar distance of layered hydrated V2O3/V3O7 heterostructure nanosheets. Electrochemical investigations were conducted to assess the effectiveness of the stacked hydrated V2O3/V3O7 heterostructure as a cathode component for Zn-ion batteries. The expanded interplanar space as a result of the introduction of water molecules facilitates the insertion/extraction of Zn ions, leading to significantly enhanced electrochemical characteristics. The layered hydrated V2O3/V3O7 heterostructure exhibited an impressive specific capacity of 330 mAh g-1 at a current density of 0.1 A g-1, maintaining a capacity retention of approximately 92.3% and a coulombic efficiency of 95.8% even after 2000 cycles.

Fabrication and characterization of a novel strontium oxide-polythiophene core–shell nanocomposite for in-vitro electrochemical detection of antiplatelet cilostazol drug in formulation and human plasma

The green synthesis of metal or metal oxide nanoparticles utilizing plants is a novel promising approach in bio-nanotechnology. The strontium oxide nanoparticles (SrO NPs) were synthesized for the first time utilizing a plant extract of Green cardamom (Elettaria cardamomum) as a reducing and stabilizing agent. The strontium oxide polythiophene (SrO@PTh) nanocomposite was then prepared by in-situ oxidative polymerization of thiophene on the surface of SrO NPs using anhydrous FeCl3 as an oxidant. FTIR spectrum indicates the coordination of SrO NPs with the binding sites along PTh backbone. TEM analysis resulted in an average particles size of (25 – 50 nm) for SrO NPs and core–shell nanostructure of its composite (SrO@PTh CS) with shell thickness of (20–90 nm). The XRD analysis indicates a crystalline cubic structure of SrO NPs with particles size of ≈ 45 nm in average and interplanar space of (0.24 ∼ 0.36 nm). The crystallinity was relatively diminished to some extent for SrO@PTh CS which exhibits a particle size of about 85 nm and interplanar space of (0.13 ∼ 0.23 nm). A smart and novel electrochemical graphite paste sensor (GPS), based on SrO@PTh CS nanocomposite, has been fabricated for the ultrasensitive in-vitro detection of antiplatelet drug cilostazol. SrO@PTh CS nanocomposite-based square-wave voltammetry biosensor exhibited the lowest limits of detection of 1.99 × 10−10 and 9.83 × 10−10 M for cilostazol drug determination in bulk and human plasma samples, respectively compared to all the reported methods. It exhibited also good reproducibility, repeatability, long-term stability and was free from biological interference effects.

Molten Na reduced T-Nb2O5 nanorods enable enhanced Na-storage performance

Abundant oxygen vacancies are generated on the surface of the T-Nb2O5 nanorods by a molten Na reduction method, which is accomplished by immersing the pristine T-Nb2O5 nanorods into a melting Na liquid for a short period (30 min) at low temperature (200 °C). The incorporation of such oxygen vacancies gives black T-Nb2O5 nanorods and brings the advantages of enhanced sodium storage capacity, rate performance, and cycle stability, which originate from the expanded interplanar space, increased electronic conductivity, and boosted ion diffusion kinetics. The optimized T-Nb2O5 nanorods electrode delivers a capacity of 100.7 mAh/g at 1C and maintains 44.1 mAh/g at 5C after 1000 cycles, which is superior to those of the pristine sample and conventional H2 reduced samples. This work proposes a new and effective method for modulating oxygen vacancies and emphasizes the importance of modulating oxygen vacancies in metal oxide electrode materials toward high-performance sodium-ion batteries.

Engineering defective trimetallic metal-organic framework nanosheets for advanced water oxidation electrocatalysis.

Limited by single metal active sites and low electrical conductivity, designing nickel-based metal-organic framework (MOF) materials with high activity and durability remains a challenge. Here, a novel class of two-dimensional trimetallic MOF nanosheets with plentiful active sites, rich metal defects, and facilitated mass and electron transfer channels is developed as efficient electrocatalysts for boosting oxygen evolution reaction (OER). The unique 2D nanosheet structure enlarges the active area; meanwhile, the organic ligand in the MOF can work as a pillar to enlarge the interplanar space to boost the ion and electron transportation, and the synergistic effect between multi-metal active sites can effectively promote the electrocatalytic activity. Interestingly, after an electrochemical activation process, the optimized NiFeZn MOF nanosheets can yield abundant metal defects, enabling them to deliver a low overpotential of 233 mV at 10 mA cm-2 with a much smaller Tafel slope of 37.8 mV dec-1. More importantly, this method is also universal for the synthesis of the NiFe-MOF family for achieving outstanding electrocatalytic OER performance. These findings present a universal strategy for the construction of a novel class of 2D trimetallic MOF nanosheets for the OER.

Structural Phase Transformation of Rail Steel in Compression

The analysis of structure and defective substructure of rail steel in uniaxial compression to a degree of 50% is carried out. It is revealed that cold hardening has a multi-stage character and is accompanied by fragmentations of pearlite grains which is in field as the degree of deformation increases and reaches ≈ 0.4 volume of the foil studied at ε = 50%. The fragments being formed in ferrite plates are separated by low-angle boundaries. The average size of the fragmented ferrite decreases from 240 nm at ε = 15% to 200 nm at ε = 50%. Concurrently with the ferrite fragmentation, fragments of cementite are also observed. It is found that the sizes of the cementite fragments are in a range of 15 to 20 nm and depend weakly on the degree of sample deformation. The cementite fragmentation is caused by deformation-induced carbon dissolution and dislocation-induced fracture. The carbon atoms diffuse from cementite crystal to dislocations, which move through an interplanar space to form particles of tertiary cementite at nanoscale (2–4 nm). It is found that the increase in the degree of deformation is accompanied by a decrease in the scalar and an excess dislocation density. A physical interpretation of the observations has been given.

Surface fractality and crystallographic texture properties of mixed and mono metallic MOFs as a new concept for energy storage devices

Herein, fractality, morphology and crystallography studies as a novel approach were introduced to evaluate the effect of inorganic nodes on energy storage device performances of Ni/Co-BTC and Ni/Zn-BTC mixed metallic (MM) and Ni-BTC, Zn-BTC, and Co-BTC mono metallic (mM) MOFs electrode materials. Through XRD data, crystallographic texture studies were pursued by calculating crystallite size (D), interplanar space (dhkl), strain and dislocation density (ε,δ), and texture coefficients (TC(hkl)). Besides statistical studies, the Areal Autocorrelation Function (AACF) via AFM analysis was developed to investigate morphological features. Fractality results of electrochemical and physical methods verified the reliability of these methods for describing the pseudocapacitive nature of MM-MOF and mM-MOF electrode materials. Based on our findings, compared with mM-MOFs, Ni/Co-BTC and Ni/Zn-BTC MM-MOF electrodes with the beneficiary of the synergistic effect of mixed-metallic cations, smaller crystallite size (D=21.53 nm), higher maximum height (Sz=21.64 nm) with larger fractal dimensions (Df=2.58), and more interface width roughness (RMS=2.65 nm) offers an impressive architecture capable of pseudocapacitance storing charge. Therefore, Ni/Co-BTC and Ni/Zn-BTC MM-MOF electrodes offer the specific capacity of 263.8 and 203.3 mA h g−1 at 2.5 A g−1 with a dominant contribution of battery-like features.

Molecular dynamics simulation of seeded crystal growth in glass

The mechanism of non-congruent growth of a crystal from glass has been sought using molecular dynamics simulations. Specifically, as a model of this process, the growth of a lithium niobate (LiNbO 3 ) crystal seed sandwiched between two lithium niobosilicate (LNS) glass slabs has been simulated as a function of time and temperature. The growth of pre-existing crystal is strongly affected by the orientation of crystal seed, temperature, and the SiO 2 concentration in the surrounding LNS glass matrix. The orientation of LiNbO 3 seed surface that has inherently larger interplanar distance results in a relatively slower crystal growth. The addition of SiO 2 to LNS system significantly decreases the crystal growth, which primarily occurs in the region devoid of Si. The suppressive effect of SiO 2 on growth rate can be traced to the existence of defect complex comprising of Si substituted at the Nb site and a nearby Nb vacancy. • Crystal growth is observed in interfacial structures containing lithium niobosilicate glasses and lithium niobate crystals. • Crystal orientation with large interplanar space results in high crystal growth rate. • High SiO 2 content suppresses the formation of ordered structures. • [Si Nb -V Nb ] defect complex exists in LiNbO 3 crystal at low SiO 2 concentration.

Structural, morphological, and optical properties of CdS and nickel doped CdS nanocrystals synthesized via a bottom-up approach

The present work investigates the effect of nickel doping with pristine cadmium sulfide (CdS) on structural, morphological, and optical properties synthesized via a bottom-up approach. The crystallite structure, size, interplanar space, lattice constants, and volume of the unit cell have been estimated from the X-ray diffraction (XRD). The average crystallite size was found in a nano range and increased with nickel incorporation. XRD result confirmed the prepared nanocrystals of CdS and transition metal Nickel doped CdS are in the hexagonal wurtzite structural phase. Field emiision scanning electron microscopy(FESEM) micrographs indicate that the nanocrystals have a smooth surface and appear to be roughly spherical and are also found in the nano range. EDAX attached with FESEM mapping studies showed the presence of the homogenous distribution of individual elements. Absorption spectra of UV–Vis spectroscopy show an effective band gap decreases after doping. This work furnishes a gateway to improve the optical properties of CdS for optoelectronic device applications by selecting the suitable proportion of transition metal dopants.

Sodium vanadate/PEDOT nanocables rich with oxygen vacancies for high energy conversion efficiency zinc ion batteries

Aqueous zinc-ion batteries (ZIBs) have received an increasing attention for large-scale energy storage due to its low cost and high safety. However, the sluggish kinetics stemming from the limited Zn2+ diffusion pathway and the strong electrostatic interaction between Zn2+ and the anion sublattice in the host crystal are great challenges for high-efficient Zn2+ storage. To circumvent these hurdles, bridge-oxygen sited oxygen vacancies are introduced in sodium vanadate Na0.76V6O15 (NVO) through the in-situ polymerization of 3,4-ethylenedioxythiophene. In the resultant oxygen-vacancy rich NVO/poly(3,4-ethylenedioxythiophene) (PEDOT) nanocables (noted as Vo¨-PNVO), the interplanar space is enlarged and the electrostatic interaction is weakened by the introduction of “oxygen vacancies” for fast reversible Zn2+ diffusion and intercalation. The conductive PEDOT coating also provides desired electronic conductivity and improves the structural integrity of NVO. Consequently, Vo¨-PNVO based ZIBs exhibit an enhanced specific capacity (355 mA h g−1 at 50 mA g−1), significantly enhanced energy conversion efficiency (>80%), and long lifespan (99% of the initial capacity remained after 2600 cycles).

Effect of Reaction Time on the rGO-CoS Composite Structural Properties

In this research, the rGO-CoS composites were successfully synthesized from GO and the Cobalt and Sulfur precursors via solvothermal reaction. The GO material was obtained by Hummer method reaction synthesis. In term of rGO synthesis, reaction time is one of important factors that determine the reduction process and the resulting material properties. Therefore, we studied the influence of reaction time to the chemical properties of the obtained composites by varying i.e 12, 24, 36 and 48 hours of reaction time. The characterizations were carried out using Scanning Electron Microscope (SEM), X-Ray Diffraction (XRD), and Fourier Transform Infra-Red (FTIR). Morphological observation of rGo-CoS shows that rGO-CoS are has many thin layers, rougher, and wider surface. From the XRD result, GO shows shift of peak diffractogram to 2θ 9.56 ° with interplanar space 9.24 Á and rGO-CoS 36 shows several peaks at 2θ 30.84, 35.47, 47.54, 54.94°. The GO spectrum pattern shows specific functional group, OH groups (hydroxyl), carboxyl stretching vibration C=O (-COOH), C=C of unoxidized graphite consisting aromatic rings, and epoxy group vibration C-O(-C), while rGO and rGO-CoS shows decrease in intensity of these bands. It concluded that the rGO-CoS 36 (hours) is considered as the most optimum reduction reaction time.

Understanding the Effect of Interplanar Space and Preintercalated Cations of Vanadate Cathode Materials on Potassium-Ion Battery Performance.

Nonaqueous potassium-ion batteries (KIBs) have been regarded as a promising alternative energy system to lithium-ion batteries, due to the abundance of the K resource and unique electrochemical properties. However, exploring suitable KIB cathode materials remains a great challenge, owing to the much larger size of the K ion than that of the Li ion. Here, a series of layered vanadates have been developed as cathodes for KIBs to elucidate the key factors that determine the electrochemical performance of KIBs, including the interlayer distance between adjacent (100) planes (d100) and preintercalated cations. Compared to NH4V3O8 nanowires with a d100 of 7.80 Å, (NH4)0.5V2O5 nanowires with a wider d100 of 9.52 Å show a faster K+ diffusion and much higher reversible capacity. The preintercalation of potassium ions into V-O slabs is also crucial to the stability of the structure of vanadates, which leads to better electrochemical cycling stability in K0.5V2O5 than that in (NH4)0.5V2O5 and NH4V3O8 nanowires. These findings reveal the great potential of the vanadate cathode in future KIBs and provide a new direction to rationally design a stable layered intercalation compound for practical KIBs.

Tuning (003) interplanar space by boric acid co-sintering to enhance Li+ storage and transfer in Li(Ni0.8Co0.1Mn0.1)O2 cathode

High nickel layered oxides (LiNi0.8Co0.1Mn0.1O2, NMC811) demonstrate high capacity (≥ 200 mA h/g) and low cost, making them increasingly attractive as a high energy active cathode to replace LiCoO2 or LiFePO4 for lithium ion batteries. Nevertheless, their large scale practical applications are still inhibited by the low structural stability, insufficient rate capability and cyclability. In this work, a stable and safe LiNi0.8Co0.1Mn0.1O2 cathode was synthesized by facile oxalic acid assisted co-precipitation method. Boric acid has been chosen and utilized as a co-sintering agent to enhance the electrochemical performance via fine tuning internal interplanar space between transition metal oxide (003) layers. The B03 sample with 3.0 at% of boron doping exhibited a sustainable reversible capacity as high as 220 mA h g−1 with approximate 97% capacity retention after 100 cycles at 0.5 C charging/discharging rate. It also delivered 93 mA h/g under 10 C rate testing. In the long-term cycling test, this B03-NMC 811 cathode demonstrated 83% capacity retention after 300 cycles at 5 C cycling test. Appropriate adding of boron not only enhanced their C-rate capability and cyclability but also improved their structural stability during repetitive charging and discharging process through ex situ XRD measurement. The c axis variation of B03-NMC 811 cathode between 3.7 V and 4.3 V was reduced by 7.6% (0.014 Å) as compared to the pristine one. However, larger quantity (5.0 at%) of boron degrades the electrochemical performance induced by increased Li/Ni disorder. Thereafter, this enhancement in both electrochemical performance and structural stability benefits from the optimized interplanar space between transition metal oxide (003) layers, which can be tuned precisely by such a simple but novel co-sintering process with boric acid. This approach opens the door to structural modification and optimization of NMC811 cathode to satisfy the demanding performance and safety requirements of electric vehicles.

Study of Phase Transitions Occurring in a Catalytic System of ncFe-NH3/H2 with Chemical Potential Programmed Reaction (CPPR) Method Coupled with In Situ XRD

Nitriding of nanocrystalline iron and reduction of nanocrystalline iron nitride with gaseous mixtures of hydrogen with ammonia were studied at 375 °C and atmospheric pressure using the chemical potential programmed reaction (CPPR) method coupled with in situ XRD. In this paper, a series of phase transitions occurring during the processes is shown, and a detailed analysis of the phase composition and the structure of the material is given. The influence of a variable nitriding potential on the lattice parameters of α-Fe, γ′-Fe4N, and ε-Fe3-2N phases is shown. The α phase interplanar space changes irrelevantly in the one phase area but decreases linearly with average increases in crystallite size when α→γ′ transformation occurs. The nanocrystallite size distributions (nCSDs) were determined, with nCSD of the α phase for nitriding and nCSD of the ε phase for reduction. The reduction of the ε phase can occur directly to α or indirectly with an intermediate step of γ′ formation as a result of ε→γ′→α transformations. The determining factor in the reducing process method is the volume of ε phase nanocrystallites. Those with V < 90,000 nm3 undergo direct transformation ε→αFe(N), and V > 90,000 nm3 transforms to αFe(N) indirectly. It was determined at what value of nitriding potential which fraction of the ε phase nanocrystallites starts to reduce

Thermoelastic properties nanocomposite chloroprene of rubber with montmorilonit

The problem that arises during the operation of tires is cyclic deformation, in which there is a conversion of mechanical energy into heat. However, due to the low thermal conductivity of rubber, repeated cyclic loads of products based on them lead to heating, which is due to the phenomenon of mechanical hysteresis. The consequence is a deterioration of their performance over time and, as a consequence, a reduction in service life.
 The main method for increasing the interfacial interaction for ceramic fillers is to ensure the penetration of rubber molecules into the interplanar space (gallery) formed by the filler particles (intercalation), and the subsequent distribution of these nanoplates (exfoliation) to a thickness of several nanometers throughout the field.
 The aim of this work is to study the thermoelastic properties of rubbers made on the basis of nanosized mineral filler montmorillonite, which may indicate a way to solve the problem of their durability.
 It was investigate the influence of modified nanosize montmorilonit on thermoelastic properties of rubber composites on it basis. It is rotined that thermoelastic properties described a model, which takes into account holdings of local increase of tension for a rubber matrix and destruction of spatial net of nanoparticles with the increase of strein, which results in exotherms which show up as a result of friction between the filler particles.
 Quantitative analysis of the thermoelastic properties of rubber nanocomposites provides additional confirmation of the concept of the reinforcement factor, which depends on the deformation, and determines the thermoelastic properties of nanocomposites for the whole range of relative elongations.

Laser-induced methods for obtaining carbon nanomaterials in liquid nitrogen under femtosecond radiation

The paper presents the experimental results of nanostructures formation under the influence of femtosecond laser radiation on carbon samples at liquid nitrogen temperatures. Two femtosecond laser systems were used to study the processes of laser action on highly oriented pyrolytic graphite and glassy carbon samples in liquid nitrogen: titanium-sapphire laser system with wavelength 800 nm, pulse duration 50 fs, energy 1 mJ, and repetition frequency of 1 kHz; ytterbium laser system with wavelength 1030 nm, pulse duration 280 fs, energy 150 µJ, and repetition frequency of 10 kHz. Cryostats, including those with the possibility of observing the laser action process, were collected for the experiments. As a result of laser action on the surface of the processed carbon samples, sheets of exfoliated graphene of various sizes and shapes (sheets, tapes, crumpled graphene), as well as nanostructures in the form of nanopeaks, were obtained. The mechanisms of graphene exfoliation under femtosecond laser action in liquid nitrogen, consisting in intercalation and further heating of nitrogen molecules in the interplanar space of graphite, were proposed. The possibilities of further research and development of technologies for graphene formation using laser radiation are presented.

Intercalated multiwall carbon nanotubes with cobalt: structure and properties

The possibility of obtaining intercalation compound with cobalt based on multiwall carbon nanotubes is considered. For intercalation the two-stage method using an intercalation compound with potassium as a precursor has been chosen. To determine the structural features of the obtained compound and the distribution of the metal in it the intercalated multiwall carbon nanotubes have been studied by X-ray diffraction, electron microscopy and thermagnetometry methods. It is shown that intercalated by cobalt multiwall carbon nanotubes are third stage compounds in which atomically distributed cobalt is into the interplanar space of nanotubes. Studies of electrical resistance have found that for intercalated multiwall carbon nanotubes, in contrast to graphite intercalation compounds, resistivity increases after intercalation process. The changes of conduction mechanisms in multiwall carbon nanotubes after intercalation have been also analyzed.

Модификация пиролизованного полиакрилонитрила атомами серебра

Recently, the search for new materials for nanoelectronics has attracted the interest of scientists. New materials, which are metal-polymer nanocomposites, can be used in modern electronics. The paper presents the possibility and mechanisms for the formation of a metal composite based on single-layer and two-layer pyrolyzed polyacrylonitrile when interacting with silver atoms. The results of the silver atom adsorption on the polymer surface are described, the possibility of filling the interlayer space with metal atoms is shown, and geometric and electron-energy characteristics are established. Theoretical calculations were performed using a molecular cluster model using a non-empirical method in the STO basis. The structure and electron-energy state of a metal-carbon nanocomposite based on pyrolyzed polyacrylonitrile with silver atoms are studied. It was found that the silver atom is adsorbed on the surface of PPAN, and the adsorption process is almost independent of the selected adsorption center. The introduction of metal atoms into the interplanar space of PPAN causes the initially planar monolayers of PPAN to bend, while the structure retains its stability. It was found that the presence of metal atoms in the PPAN structure causes a change in the band gap, which leads to a change in the conductive properties of the resulting nanocomposite.

Use of Zinc-Aluminum Layered Double Hydroxides as Nanofillers of Thermoplastic Vulcanizates

The synthesis of layered double hydroxides based on zinc and aluminum salts containing nitrate anion in the interplanar space is described. The samples prepared were investigated by X-ray structural analysis. It was found that the interplanar distance of brucite layers is 8.6 nm. The prepared samples were modified with stearate anions. X-ray diffraction spectra of the modified samples show that there was a complete substitution of the nitrate anion for the stearate anion, and the interplanar distance increased to 46.8 nm. Nanocomposites of dynamically crosslinked thermoplastic elastomer based on ethylene–propylene rubber and polypropylene in a ratio of 70 : 30 were produced using 3, 5, 7 wt. parts of modified double hydroxide. A significant increase in the physical and mechanical properties, as well as an increase in heat resistance and fire resistance of the sinthesized nanocomposites, has been established.