Structure Of Nanocubes Research Articles

ZIF-67 Derived Co2VO4 Hollow Nanocubes for High Performance Asymmetric Supercapacitors.

In this work, a new type of Co2VO4 hollow nanocube (CoVO-HNC) was synthesized through an ion exchange process using ZIF-67 nanocubes as a template. The hollow nanocubic structure of the CoVO-HNC provides an abundance of redox sites and shortens the ion/electron diffusion path. As the electrode material of supercapacitors, the specific capacitance of CoVO-HNC is 427.64 F g−1 at 1.0 A g−1. Furthermore, an asymmetric supercapacitor (ASC) was assembled using CoVO-HNC and activated carbon (AC) as electrodes. The ASC device attains an energy density of 25.28 Wh kg−1 at a high-power density of 801.24 W kg−1, with 78% capacitance retention after 10,000 cycles at 10 A g−1.

Phytic Acid Doped Polyaniline as a Binding Coating Promoting Growth of Prussian Blue on Cotton Fibers for Adsorption of Copper Ions

In recent years, the elimination of heavy metals from wastewater has become an important topic due to rapid industrialization, and it is of considerable interest to develop renewable and degradable materials for this purpose. In this work, a novel Prussian blue/polyaniline@cotton fibers (PB/PANI@CFs) composite was fabricated by a two-step process. Phytic acid doped PANI as a binding coating greatly promoted both the growth of PB and the adsorption of Cu2+. The deposition ratio of PB was as high as 24.68%. Scanning electron microscopy (SEM) displayed that PB nanoparticles were grown more uniformly in the composite and formed a perfect nanocube structure compared with PB@CFs. The successful deposition of both PB and PANI on CFs was demonstrated by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FITR), and X-ray photoelectron spectroscopy (XPS). The effect of adsorption time, adsorbent dose, initial pH value, and initial copper sulphate concentration on the adsorption of PB/PANI@CFs composite for Cu2+ was studied by static adsorption and was compared with those of PANI@CFs and PB@CFs. The results showed that the maximum removal efficiency of Cu2+ by PB/PANI@CFs can reach 93.4% within 5 h, and the maximum adsorption capacity of Cu2+ can reach 31.93 mg·g−1. The adsorption of Cu2+ on PB/PANI@CFs followed the pseudo-second order kinetic model and conformed to the Freundlich adsorption isothermal model. The PB-functionalized CFs provided new insights into the design of efficient and low-cost absorbents for heavy metal remediation. The proposed process solves two problems simultaneously, i.e., the utilization of environmentally friendly and biodegradable biomass resources and the adsorption of heavy metal ions, and is a good approach to achieve high-quality and sustainable development.

One-dimensional self-assembled Co2SnO4 nanosphere to nanocubes intertwined in two-dimensional reduced graphene oxide: an intriguing electrocatalytic sensor toward mesalamine detection

The present work deals with the preparation of hybridized electrode material with electrostatic self-assembly strategy for mesalamine (MES) detection. Grabbing significant abilities between the one-dimensional bimetallic oxides and two-dimensional nanosheets network, a nanohybrid was designed. The developed cobalt stannate/reduced graphene oxide (Co2SnO4/rGO)-1D/2D heterostructure will possess improvised anisotropic electron transport, earth abundant, highly conducting, multiple actives site, and higher surface area. The 1D/2D nanostructured architecture will enhance faster electron and mass transport during the electrochemical analysis, which is more significant for MES detection. Progressive testing of Co2SnO4/rGO for structural analysis was done, and highly crystalline nature was proved. The self-assembled nanospheres to form nanocube such as Co2SnO4 strongly attached over the rGO matrix was confirmed with field emission scanning microscope, and nanocube structure is more visible with high-resolution transmission electron microscopy. The hierarchical highly electroactive material establishes lower detection limit at 4.9 nM with sensitivity of about 8.57 μA/μM/cm2. The interfacial area of nanocomposite with higher conducting channels to improve the interactions with MES resulted in enhanced selectivity. The practical analysis in environmental, pharmaceutical, and biological fluids (human urine and serum) showed good recovery. The Co2SnO4/rGO will be more prominent and significant as electrode material in electrochemical sensing.

Lithium-Storage Performance and Mechanism of a (Ni0.5Co0.5)9S8@NC Hollow Nanocube Composite as an Advanced Anode

In this work, the lithium-storage performance and mechanism of a designed (Ni0.5Co0.5)9S8@NC hollow nanocube composite as a rechargeable lithium-ion battery (LIB) anode are investigated. The nanocomposite is composed of a bimetallic sulfide (Ni0.5Co0.5)9S8 core and a surrounding nitrogen-doped carbon shell. It displays a superior electrochemical reactivity with an appealing specific capacity of 724 mAh g–1 at a specific current of 0.5 A g–1 cycled 80 times, as well as attractive stability and rate capability. The quantitative kinetic analysis reveals that the advanced lithium-storage performance is partly derived from the pseudocapacitive contributions. In situ X-ray diffraction (XRD) demonstrates the formation of Ni, Co, and Li2S in the conversion reaction during the initial cycling. Ex situ transmission electron microscopy (TEM) and scanning electron microscopy (SEM) demonstrate the volume expansion of the core (Ni0.5Co0.5)9S8 active material with the essential preservation of the complete (Ni0.5Co0.5)9S8@NC hollow nanocube structure during repeating cycling. Namely, the synergistic effect of the N-doped carbon coating, the rigid hollow nanostructure, and the multiple-electron-transfer conversion reaction of the bimetallic sulfide contributes to the superior lithium-storage performance of the nanocomposite.

Design and fabrication of hollow structured Cu2MoS4/ZnIn2S4 nanocubes with significant enhanced photocatalytic hydrogen evolution performance

The unique architecture is very significant for photocatalysts to achieve high photocatalytic efficiency. Herein, hollow Cu2MoS4/ZnIn2S4 heterostructural nanocubes with intimate-contact interface have been prepared for the first time via a self-template way, which can promote the photocatalysis hydrogen evolution. First, novel hollow structured Cu2MoS4 nanocubes were successfully synthesized using Cu2O as a precursor, then the ZnIn2S4 nanosheets were in-situ grew on the surface of hollow Cu2MoS4 nanocubes. The unique hollow heterostructures have markedly enhanced photocatalytic efficiency, and 15 wt% Cu2MoS4/ZnIn2S4 sample exhibits the highest hydrogen production rate of 8103 μmol·h−1·g−1, which is approximately four times higher than pure ZnIn2S4. The improved photocatalytic performance is mainly attributed to the following two points: (1) the hollow nanocube structure can provide rich active sites and increase light absorption; (2) forming a built-in electric field is conducive to transfer the holes generated by ZnIn2S4 to Cu2MoS4, which can effectively promote charge separation. This work may provide insights for the design of hollow architecture cage materials for high photocatalytic performance.

Preparation of SrTiO3/Bi2S3 Heterojunction for Efficient Photocatalytic Hydrogen Production

SrTiO3, Bi2S3, and SrTiO3/Bi2S3 heterojunction were prepared for efficient photocatalytic hydrogen production. SrTiO3/Bi2S3 heterojunction was prepared by different weight percentages of Bi2S3 (1, 3, 5, and 7%) with SrTiO3. SrTiO3 and Bi2S3 are exhibited in cubic and orthorhombic crystal structures, respectively. The morphologies of SrTiO3 and Bi2S3 have existed as nanocubic and bar-like structures, respectively. Transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) results further confirmed the formation of SrTiO3/Bi2S3 heterojunction. The photoluminescence (PL) and electrochemical impedance spectroscopy (EIS) results indicated that the SrTiO3/Bi2S3 heterojunction reduces the rate of photogenerated electron–hole pair recombination and electron-transfer resistance than pure SrTiO3 and Bi2S3. The formation of SrTiO3/Bi2S3 heterojunction effectively separates the photogenerated charge carriers, which enhances the photocatalytic hydrogen production under UV light. The SrTiO3/Bi2S3 heterojunction shows superior photocatalytic hydrogen production than bare SrTiO3 and Bi2S3 due to the synergistic effect. The photocatalytic hydrogen production of SrTiO3/Bi2S3 (5%) gives 7.7 mmol g–1 within 180 min under UV irradiation.

Facile synthesis of hierarchical NiCoP nanosheets/NiCoP nanocubes homojunction electrocatalyst for highly efficient and stable hydrogen evolution reaction

Designing and synthesizing stable, low-cost, and eco-friendly precious-metal-free electrocatalysts with high performance for hydrogen evolution is a critical and challenging task in the research and development of renewable hydrogen energy. Herein, we show an interfacial engineering strategy to synthesize the NiCoP nanosheets/NiCoP nanocubes homojunction electrocatalyst supported on Ni foam (2D/3D-NiCoP/NF). The as-synthesized 2D/3D-NiCoP/NF catalyst shows impressive HER activity, and a current density of 10 mA cm−2 can be achieved with only an overpotential of 37 mV in 1 M KOH solution. Such impressive HER performance of this 2D/3D-NiCoP/NF homojunction electrocatalyst is principally due to the exposure of abundance accessible active sites originated from the hierarchical structure of nanocubes on the nanosheets. Moreover, the intimate contact between 2D/3D-NiCoP and NF can simultaneously shorten the electron transport pathway and improve its stability. This novel 2D/3D-NiCoP/NF homojunction is expected to provide a powerful interface-engineering reference for the design and construction of high-efficiency synergistic HER electrocatalysts.

Introducing a self-improving catalyst for hydrogen evolution and efficient catalyst for oxygen evolution reaction

Herein, MoS2/Ni3S2 nano-cubic rods (NCR) is fabricated on Ni foam via a two-step process including modified solution method and thiourea phosphate-assisted strategy. The resultant material serves as a self-improving high intrinsic catalyst for hydrogen evolution reaction (HER), and exhibits desirable activity for oxygen evolution reaction (OER) in alkaline media. Results demonstrated that two different phases of MoS2 and Ni3S2 along with the presence of abundant active sulfur edge sites and particular structure lead to the enhanced electrocatalytic activity. The most interesting point is the self-improving behavior of MoS2/Ni3S2 NCR by proceeding the HER. It means by time and catalyzing the hydrogen evolution reaction the performance of catalyst improved, so that after long time HER the catalyst reaches 10 and 20 mA cm−2 at overpotential of 40 and 85 mV, respectively. It is found that the improvement in catalytic performance can be assigned to the charge transfer enhancement and increasing in active surface area as HER proceeds. Further, characterization investigations show that thiourea phosphate-assisted strategy plays a key role to attain the nano-cubic rods structure. Indeed, the generated MoS2 nanolayers act as a substrate for anchoring and growing of Ni3S2 nano-cubic particles and consequently lead to preparation of cubic nano rods structures. Besides, low onset potential with the overpotential of 200 mV was obtained for OER using MoS2/Ni3S2 NCR.

PbSe/sulfur-doped carbon nanocube composites prepared from Pb-MOF precursors as anode materials for lithium and sodium-ion batteries

PbSe/sulfur-doped carbon (SC) nanocube composites were successfully synthesized by a simple two-step method. Firstly, the lead-based metal organic framework (Pb-MOF) materials were synthesized by a simple room-temperature aqueous solution method. Then the Pb-MOF materials were used as precursor to react with selenium powder to prepare PbSe/SC nanocube composites in a vacuum quartz tube under high temperature. As the anode materials for lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs), the PbSe/SC nanocube composites exhibit excellent electrochemical performance, because the special microporous nanocube structure can provide more active sites for redox reaction and effectively reduce the volume expansion of PbSe materials, and sulfur-doped carbon can increase the electronic conductivity of the material. The PbSe/SC nanocube composites showed excellent high-rate performance (818.5 mAh g−1 after 800 cycles in LIBs at 2000 mA g−1) and cyclic performance (717.1 mAh g−1 in LIBs and 313.6 mAh g−1 in SIBs after 100 cycles at 100 mA g−1). The results show that PbSe/SC nanocube composites have great potential as anode materials for LIBs and SIBs.

Porous ZnSnO3 nanocubes as a triethylamine sensor

• ZnSnO 3 was fabricated by a microwave-assisted hydrothermal method and calcination. • ZnSnO 3 presented a nanocubic and porous structure. • Porous ZnSnO 3 nanocubes presented sensitivity and selectivity to triethylamine. • High response and fast response time toward triethylamine detection were attained. • The sensor showed a low detection limit (∼0.6 ppm) to triethylamine detection. Triethylamine (TEA), a volatile organic compound (VOC), is present in several industrial processes and is harmful to human health. Therefore, the development of highly sensitive TEA sensors is desirable. Semiconductor metal oxides (SMOx) have been widely used for VOCs detection due to their efficiency and feasibility. Herein, we report the template-free synthesis of zinc stannate nanocubes (NC-ZnSnO 3 ) by the microwave-assisted hydrothermal method followed by a calcination step. The sample's sensing properties were investigated for different VOCs (methanol, ethanol, isopropanol, acetic acid, acetone, 2-butanone, acetaldehyde, benzene, toluene, m-xylene, and TEA). The sensor presented an improved selectivity toward TEA, showing the highest response of 57.5 to 100 ppm of TEA with a fast response time of 4 s at the optimum operating temperature of 350 °C. The NC-ZnSnO 3 also showed a low detection limit for TEA of about 0.6 ppm. In summary, this work described an efficient method for producing NC-ZnSnO 3 and demonstrated that this material has high selectivity and sensitivity for TEA detection.

Screen‐printing of nanocube‐based flexible microchips for the precise biosensing of ethanol during fermentation

AbstractThe real‐time and full concentration analysis of ethanol during the fermentation reaction allows the precise control of the microbial metabolism to promote the conversion rate; however, only few techniques can directly detect the fermentation broth without pretreatment. To address this issue, a screen‐printed biosensing microchip (SPBM) was proposed to analyze the ethanol concentration in fermentation, relying on designing a well‐defined nanocubic structure of an Au nanoparticles/nickel hexacyanoferrate nanocomposite. This nanocomposite was then made into a printing ink for the direct fabrication of a SPBM. The as‐prepared microchip exhibits an ultrahigh electrocatalysis on nicotinamide adenine dinucleotide with a high sensitivity of 96.2 ± 2.9 μA·mM−1·cm−2. Moreover, after the immobilization of alcohol dehydrogenase, the accurate and rapid monitoring of the ethanol concentration during the real fermentation reaction can be realized within an ultrawide linear range of 0.1–10 M in the broth without any pretreatment.

Hydrothermally synthesized NiCo2O4 nanostructures for energy storage applications

Over the past decades, depleting fossil energy and global warming has made it imperative to develop clean, efficient and sustainable energy sources. Among the existing energy storage devices, supercapacitors are attractive systems due to their high power density and excellent cycling stability. In the present study, NiCo2O4 nanostructures are synthesized via hydrothermal route using different structure directing reagents for effectively assigning in supercapacitors as excellent electrodes. The as-synthesized structures are scrutinized using various characteristic tools for examining their properties. X-Ray Diffraction analysis of the samples confirms NiCo2O4 crystallite phases in the as-synthesized structures. Scanning Electron Microscopy of the samples reveal the structure of nanocubes and nanourchins for the two different as-synthesized samples. Brunaueur Emmett Teller study for analyzing surface properties of the samples illustrates higher surface area for nanocubes than nanourchins. Further, to investigate the electrochemical performance of nanodandelions, the samples were subjected to electrochemical impedance spectroscopy analysis and it is found to be illustrated with outstanding cyclic stability and capacitive performance.

Structural and electronic properties of InGaAs, InGaP and InGaSb nanostructures – A density functional theory approach

The realistic clusters of InGaAs, InGaP and InGaSb were completely optimized using density functional theory. The stable geometry of different isomers namely bucky ball, nanotube and nanocube were studied using calculated energy, dipole moment and point symmetry. The electronic properties were studied in terms of HOMO-LUMO gap, ionization potential and electron affinity. The bucky ball structures have the high value of HOMO-LUMO gap. Low value of ionization potential was noticed for the nanocube structure. The nanotube structures have high electron affinity. The nanocube isomers have the highest binding energy and embedding energy. The bucky ball isomers have the maximum chemical hardness. The least value of chemical potential was seen for nanocube isomers. The information provided in this study will give a clear picture to tailor new materials which finds its potential application in the optoelectronics.

Hollow bimetallic selenide derived from a hierarchical MOF-based Prussian blue analogue for urea electrolysis

PBA@MOF–Ni/Se with a nanocube structure grown on a flower-shaped MOF–Ni template exhibits better performance in urea electrolysis.

Construction of three-dimensional ZnCo2O4 hierarchical nanocubes for enhanced lithium storage performances

Three-dimensional (3D) transition metal oxides have been intensively researched as the potential electrode materials for high capacity lithium storage. Herein, the 3D hierarchical ZnCo2O4 consists of many nanocubes which are constructed through a facile hydrothermal method combined calcination process. Such 3D hierarchical nanocube structures with abundant porous can effectively relieve large volume change and facilitate the transportation of ions and electrons under cycling process. Consequently, the 3D ZnCo2O4 nanocubes as electrode materials deliver high reversible specific capacities of 775 mAh g−1 after 100 cycles at a large current density of 500 mA g−1 and superior rate capability.

Preparation and electrochemical properties of Fe/Fe3O4@r-GO composite nanocage with 3D hollow structure

Fe/Fe3O4@r-GO composite nanocages with a hollow porous heterostructure, which look like “flower cluster,” are prepared by a mild, simple, and flexible method, followed by a thermal treatment. Metal-organic framework Prussian blue (PB), used as a precursor of Fe3O4, possesses a special hollow porous morphology, which is able to shorten transmission path and relives the mechanical stress during charge/discharge cycles. Verified by SEM and TEM characterizations, the Fe/Fe3O4 nanocage coated with uniform graphene sheets is achieved. Furthermore, XRD and XPS analysis combined with TEM results also prove that the composite is mainly composed of Fe, Fe3O4, and C. A series of electrochemical tests show that Fe/Fe3O4@r-GO composite electrodes exhibit a superior reversible capacity, rate capability, and cycling stability. The composite delivers a high reversible capability of 1200 mAh g−1 after 160 cycles at a current density of 100 mA g−1. Especially, when the current density is increased to 1000 mA g−1, the composite delivers a capacity of 455 mAh g−1. Even at a current density of 2000 mA g−1, a capacity of 355 mAh g−1 is retained. The outstanding electrochemical performances are mainly attributed to the integrity of hollow porous nanocube structure and doping of moderate graphene, which enables to promote the conductivity of electrode and build a continue network between Fe/Fe3O4 nanocubes to further accelerate ion/electron migration rate and relieve mechanical stress during cycles.

Prussian Blue Analogues–Derived CoFe–B Nanocubes with Increased Specific Surface Area and Modulated Electronic Structure as Enhanced Oxygen Evolution Electrocatalysts

Questing for efficient and inexpensive catalysts for electrochemical water splitting is vital for energy conversion and storage. Herein, Prussian blue analogues (PBA)‐derived CoFe‐based nanomaterials with increased specific surface area and abundant catalytic active sites are utilized as efficient and durable electrocatalysts for oxygen evolution reaction (OER). Due to the adjustable chemical conformation and controllable 3D morphology, CoFe–B nanocubes exhibit an ultrathin nanosheets–wrapped nanocube structure with excellent electrocatalytic performance and remarkable reaction kinetics in 1.0 m KOH aqueous solution. In addition, CoFe–B nanocubes cost overpotentials of 261 and 338 mV at corresponding current densities of 10 and 200 mA cm−2, respectively, with small Tafel slope of 61 mV dec−1 for OER, which displays higher catalytic capability than the reported commercial RuO2. The outstanding electrocatalytic performance can be mainly attributed to the unique ultrathin nanosheets–wrapped nanocube structure which is generated from calcination. This work not only provides a new way for the application of PBA but also obtains an alternative for efficient electrocatalysis.

Hierarchical porous Co3O4 nanocages with elaborate microstructures derived from ZIF-67 toward lithium storage

Increasing the complexity of external or internal structure of hierarchical nanomaterials is essential to improve the specific capacity and stability of anode for lithium ion batteries (LIBs). Three types of porous Co3O4 nanocubes (concave-cube, yolk-shell cube and porous cube) with novel hollow structures were synthesized straightforwardly by annealing zeolitic imidazolate framework (ZIF-67) under varied temperatures of 350 °C, 450 °C and 550 °C, respectively. Consequently, the resulting concave, core-shell and porous Co3O4 nanocubes exhibited superior specific capacities of 1009, 1148 and 696 mA h g−1, respectively, at a current density of 200 mA g−1 after 200 cycles. Even at a high current density of 10 A g−1, the core-shell Co3O4 nanocube still showed a large reversible capacity of 317 mA h g−1. The complex hierarchical texture, porous shell and core, and well-defined hollow structure of the Co3O4 nanocubes were contributed greatly to the good lithiation/delithiation reversibility, ultralong cycling stability and enhanced rate capability.

The Effect of Deposition Time on the Properties of Cu2O Nanocubes Using an Electrochemical Deposition Method

In this investigation, the impact of electrodeposition time on the photoelectrochemical characteristics of a cuprous oxide (Cu2O) nanocube semiconductor photoelectrode is investigated. The Cu2O nanocube photoelectrode was synthesized electrochemically, utilizing underpotential deposition (UPD). Numerous techniques, including x-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDX), ultraviolet–visible (UV–Vis) spectroscopy, linear sweep voltammetry (LSV) and chronoamperometry (CA), were utilized for characterization of the Cu2O nanocube photoelectrode. A highly crystalline structure of Cu2O nanocubes deposited on an indium tin oxide (ITO) substrate can be seen in the XRD results. SEM images revealed a cubic-shaped structure of Cu2O. However, EDX analysis and the optical bandgap confirmed the presence of uniform single-phase Cu2O nanocubes. Astonishingly, the Cu2O nanocube photoelectrode electrodeposited for 15 min possesses the highest photocurrent among all investigated films. Also, the Cu2O nanocubes displayed stable photocathodic performance as a result of the p-type nature. Moreover, the Cu2O nanocube photoelectrode is suggested to be a good candidate for progressive photoelectrochemical detection. Furthermore, it can be utilized for the expanded field of photoelectrochemical water splitting in addition to other solar photovoltaic devices.

Synthesis of Honeycomb-Like Co3S4/MoS2 Composites with Hollow Structure As Anode Materials for High-Performance Lithium-Ion and Sodium-Ion Batteries

Hollow honeycomb-like Co3S4/MoS2 composites were fabricated through the zeolitic imidazolate framework-67 (ZIF-67) as a precursor and followed by two sulfuration processes. Co3S4 hollow nanocubes were first prepared using ZIF-67 and thioacetamide co-pyrolysis. Then, MoS2 nanosheets were grown on the surface of Co3S4 nanocubes and formed Co3S4/MoS2 hollow composites. The outside flake-like MoS2 interlaced together, thus formed a honeycomb-like structure. The combination of Co3S4 and MoS2 significantly improved the electrochemical performance compared with single Co3S4 or MoS2. The presence of honeycomb-like MoS2 not only stabilized the structure of inner Co3S4 nanocubes to the maximum extent during the discharge/charge process, but also supplied more Li+ and Na+ insertion/extraction sites, increased the contact area between electrode material and electrolyte, and restrained volume expansion of inner Co3S4 nanocubes. The capacity of the Co3S4/MoS2 was maintained at 365 mAh g−1 during 1000 cycles at 1 A g−1 when used as anode material in lithium-ion batteries. At even a higher current density of 2 A g−1, the capacity of the Co3S4/MoS2 stabilized at 248 mAh g−1 during 1000 cycles. When used as anode material in sodium-ion batteries, it still has a capacity of 230 mAh g−1 at 1 A g−1, which is superior to that of the single Co3S4 nanocubes. Co3S4/MoS2 composites exhibited enhanced capacity and excellent cycling performance due to its complementarity, hollow structure and synergetic effect between Co3S4 and MoS2.