O4 Nanostructures Research Articles

Efficient Disposal of Basic Fuchsin Dye from Aqueous Media Using ZrO2/MgMn2O4/Mg(Mg0.333Mn1.333)O4 as a Novel and Facilely Synthesized Nanocomposite

In this work, amorphous and crystalline novel products based on Zr, Mg, and Mn were facilely fabricated through the Pechini sol–gel procedure using inexpensive chemicals and an uncomplicated apparatus. Also, these products showed high efficiency as novel adsorbents in getting rid of basic fuchsin dye from aqueous solutions. The adsorbent, which was fabricated before calcination, was abbreviated as KE. In addition, the adsorbents, which were created at 500 and 700 °C, were designated as KE500 and KE700, respectively. The created adsorbents were characterized using high-level transmission electron microscopy (HR-TEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), N2 adsorption/desorption analyzer, and field emission scanning electron microscope (FE-SEM). The XRD showed that the KE adsorbent is amorphous, whereas the KE500 and KE700 adsorbents are mixtures of ZrO2, MgMn2O4, and Mg(Mg0.333Mn1.333)O4 nanostructures. The HR-TEM exhibited that the KE adsorbent consists of very fine irregular shapes, whereas the KE500 adsorbent contains quasi-spherical particles with a mean diameter of 45.16 nm. Furthermore, the HR-TEM exhibited that the KE700 adsorbent consists of polyhedral shapes with a mean diameter of 76.28 nm. Furthermore, the BET surface area of the KE, KE500, and KE700 adsorbents is 67.85, 20.15, and 13.60 m2/g, respectively. Additionally, the elimination of basic fuchsin dye by the KE, KE500, and KE700 adsorbents is exothermic, physical in nature, and follows the pseudo-first-order as well as Langmuir equations. Further, the maximum uptake capabilities of the KE, KE500, and KE700 adsorbents toward basic fuchsin dye are 239.81, 174.83, and 93.19 mg/g, respectively.

Optical and temperature-dependent magnetic properties of Mn-doped CoFe2O4 nanostructures

Understanding and untangling magnetic materials are essential to implanting these materials for practical industrial applications. This work demonstrates how manganese (Mn) doping can significantly advance cobalt ferrite's magnetic and optical characteristics. We applied the hydrothermal approach to synthesize cobalt ferrite nanostructures, followed by Mn doping, to acquire CoMnxFe2−xO4 (0 ≤ x ≤ 0.1) nanostructures. The crystal structure of all the specimens confirms the formation of Fd-3 m space growth with a typical cubic structure. The estimated crystallite size values vary between 19.8 and 25.8 nm, and the lattice parameter significantly enhances from 8.31 Å to 8.38 Å as a result of Mn substitution. The fast Fourier transform infrared spectroscopy (FTIR) was performed between 400 and 4000 cm-1. The lattice vibrations ranging υ1 = 614–607 cm-1 and υ2 = 428–426 cm-1 were assigned to tetrahedral and octahedral sites, respectively. The high-resolution transmission electron microscopy (HRTEM) analysis further confirms the crystalline structure of CoMnxFe2−xO4. The room temperature magnetic measurements investigate that the magnetic coercivity of CoMn0.2Fe1.8O4 nanostructures is maximum (∼ 800 Oe) which was opted for temperature-dependent measurements. The low-temperature magnetic characteristics agree with Bloch's and Kneller's laws for saturation magnetization and coercivity of CoMn0.2Fe1.8O4 nanostructures. The optical properties confirm a blueshift and slight increment in bandgap energy of CoMnxFe2−xO4 nanostructures.

Rare Earth Doping Engineering Tailoring Advanced Oxygen-Vacancy Co3 O4 with Tunable Structures for High-Efficiency Energy Storage.

Co3 O4 with high theoretical capacitance is a promising electrode material for high-end energy applications, yet the unexcited bulk electrochemical activity, low conductivity, and poor kinetics of Co3 O4 lead to unsatisfactory charge storage capacity. For boosting its energy storage capability, rare earth (RE)-doped Co3 O4 nanostructures with abundant oxygen vacancies are constructed by simple, economical, and universal chemical precipitation. By changing different types of RE (RE=La, Yb, Y, Ce, Er, Ho, Nd, Eu) as dopants, the RE-doped Co3 O4 nanostructures can be well transformed from large nanosheets to coiled tiny nanosheets and finally to ultrafine nanoparticles, meanwhile, their specific surface area, pore distribution, the ratio of Co2+ /Co3+ , oxygen vacancy content, crystalline phase, microstrain parameter, and the capacitance performance are regularly affected. Notably, Eu-doped Co3 O4 nanoparticles with good cycle stability show a maximum specific capacitance of 1021.3Fg-1 (90.78mAhg-1 ) at 2Ag-1 , higher than 388Fg-1 (34.49mAhg-1 ) of pristine Co3 O4 nanosheets. The assembling asymmetric supercapacitor delivers a high energy density of 48.23Whkg-1 at high power density of 1.2kWkg-1 . These findings denote the significance and great potential of RE-doped Co3 O4 in the development of high-efficiency energy storage.

Anodic growth and pre-calcification on β-Ti-40Nb alloy: Effects on elastic modulus, electrochemical properties, and bioactivity

This study evaluated the surface optimization of β-Ti-40Nb alloy in terms of corrosion and bioactivity properties. Electrochemical anodization at different voltages was used to synthesize (Ti,Nb)O2 nanostructures (nanopores (NPs)) and (nanotubes (NTs)) on samples' surfaces, allowing the analysis of their influence on performances related to those properties. Then, (Ti,Nb)O2 NPs and NTs were annealed at 550 °C to crystallize the previously obtained amorphous (Ti,Nb)O2 into a mixture of anatase and rutile. Also, a pre-calcification process (PC) was applied on annealed (Ti,Nb)O2 NPs and NTs. SEM micrographs showed the presence of NTs (10 V) and NPs (20 V) after anodization. After annealing, the morphology of (Ti,Nb)O2 NPs and NTs remained constant for both diameter and length. XRD analysis confirmed that as-anodized amorphous (Ti,Nb)O2 was crystallized, after annealing, into a mixture of anatase-rutile phases. Corrosion properties were evaluated through the open circuit potential (OCP), potentiodynamic polarization curves, and electrochemical impedance spectroscopy (EIS). Samples were immersed in a simulated body fluid (SBF) solution for one to 14 days to assess the bioactivity. The bioactivity evaluation was carried out by mass gain. Also, the amount of apatite precipitated on the sample's surface was determined through SEM-EDS. The results showed that PC samples presented similar corrosion properties compared to the annealed samples. However, PC processing improved the bioactivity (apatite formation) of (Ti,Nb)O2 NTs and NPs modified β-Ti-40Nb alloy.

Nickel Cobaltite Nanoplate-Based Electrochemical Sensing Platform from Printable Inks for Simultaneous Detection of Dopamine and Uric Acid.

2D metal oxide-based nanomaterials have emerged as an exciting area of research owing to their rich electrochemical properties and diverse applications, including biosensors. In this work, we have synthesized ultra-thin Co3 O4 , NiO, and NiCo2 O4 nanostructures supported on a carbon cloth and printed graphite/Kapton substrates following thermal reduction of self-assembled metal alkanethiolates. These nanostructures act as a sensing platform for simultaneous detection of dopamine (DA) and uric acid (UA), important biological molecules in physiological and pathological tests. The ultrathin 2D nanoplates of NiCo2 O4 spinel formed in this study exhibit high electrochemical activity than pristine NiO and Co3 O4 . The electrochemical characterization studies indicate that NiCo2 O4 possesses a high potential for DA and UA with a peak separation of ∼140 mV, high sensitivity, and excellent selectivity. The low-cost and disposable, single-shot probe biosensors fabricated in this work possess a wide working range of 0.001-1000 μM with detection limits of 0.33 and 0.49 nM for DA and UA, respectively, with a practically achievable limit of quantification of ∼1 nM. Multiple sensing electrodes are printed on graphite/Kapton all at once following this method with improved reproducibility for DA and UA sensing further extending the scope of work towards mass fabrication and practical usage.

Assessment of anodization conditions and annealing temperature on the microstructure, elastic modulus, and wettability of β-Ti40Nb alloy

In this work, it was mapped combinations of anodization conditions, annealing temperatures, and elastic modulus together with better wettability properties of low elastic modulus Ti40Nb alloy. The anodization was realized in an organic electrolyte for one hour. Thus (Ti,Nb)O2 nanostructures grew on the surface. For the sake of optimizing the wettability, the anodization voltage was varied to obtain different nanostructured morphologies, which grew either in the form of nanotubes or nanopores. Posterior heat treatment at different temperatures (450°C, 550°C, and 800°C) led to distinct titania crystalline phases (anatase, anatase+rutile, rutile) and different Young's moduli. Different morphologies and crystalline phases affect surface wettability properties. Although all the studied conditions showed a hydrophilic behavior (contact angle below 90 °), the optimized condition was found to be the samples coated with anodized nanotubes, whose annealing temperature led to a mix of anatase and rutile phases. Such morphology and phases reduced the contact angle to a minimum. The annealing temperature led the alloy elastic modulus to the lowest value (65 GPa). The optimized condition may be considered the more suitable combination for future biomedical applications.

Morphology, structural and photoluminescence properties of shaping triple semiconductor YxCoO:ZrO2 nanostructures

In the present investigation, YxCoO:ZrO2 (x = 0.1, 0.3, 0.4) nanostructures (NS) are synthesized by co-precipitation and surface reduction methods using triethanol amine as surfactant and hydrazine hydrate as reducing agent. Triple-shaped semiconductor crystal features, morphology, optical absorptivity and chemical composition are determined by XRD (X-ray diffraction), FTIR (Fourier transform infrared spectroscopy), SEM (scanning electron microscopy), UV–Vis and X-ray photoelectron spectroscopy. XRD patterns revealed mixed phase of tetragonal and cubic structure of YxCoO: ZrO2 with less impurity peaks. SEM morphology indicates nanoparticles (NPs) of YxCoO:ZrO2 spherical in nature with particle agglomerations. Average Grain size, grain boundary and interpore diameter were found to be ~ 55 nm, ~ 78 nm and ~ 115 nm, respectively. FTIR spectra of YxCoO:ZrO2 (0 ≤ x ≤ 0.4) show stretching and bending peaks at ~ 533/cm (O–Y–O bond), ~ 1024/cm (Zr–O–Zr bond), broad peak at ~ 3319/cm (Y–OH) and optical absorptivity of YxCoO:ZrO2 (0 ≤ x ≤ 0.4) with λmax spread over 286 nm to 270 nm, and absorption edges appeared in between 189 and 254 nm. Chemical compositional analysis exhibited binding energies of singlet O1s at 529.8 eV, Y 3d 5/2 and Y 3d3/2 observed at 157.8 eV and 163.9 eV, respectively, while Zr 3d5/2 and Zr 3d3/2 are observed at 180.4 eV and 182.7 eV. Photoluminescence spectrum (PL) of YxCoOZrO2 NS exhibit peaks centred around ~ 455 nm (UV region) in case of Y0.4Co0.5OZr0.1O2 NS and for Y0.3Co0.5OZr0.2O2 NS ~ 538 nm (visible region) with various Y-, O- and Co-related native defects. Emission band was observed at UV region with ~ 415 nm to ~ 480 nm broad peak (Y0.4Co0.5OZr0.1O2 NS, λexcitation = 380 nm) and ~ 502 nm to ~ 582 nm in case of Y0.3Co0.5OZr0.2O2 NS with λexcitation = 410 nm. PL emission spectra of YxCoO:ZrO2 have two emission peaks centred at ~ 455 nm and ~ 538 nm with emissions bands with blue and green wavelengths. The transitions can be ascertained with shielding of 4f shells of Y+3 ions by 6s, 5d shells by the interaction of the other Y+3 ions.

(Invited) Effective Engineering of Copper-Cobalt Oxide Nanostructures for Water Splitting

The low-cost and low-toxic copper-cobalt oxide, CuCo2O4 have attracted a great deal of research interest owing to their wide range of applications such as oxygen evolution reaction, oxygen reduction reaction, hydrogen evolution reaction, alcohols oxidation, H2O2 decomposition, urea oxidation, and energy storage. Their controllable composition, electronic structure, valence states or redox characteristics, morphology, and high catalytic property have made them suitable as universal catalysts. However, their low intrinsic electrical conductivity still overshadows their practical application to some degree. In addition, The conventional preparation procedures of copper-cobalt oxide result in relatively low catalytic activity or large OER overpotential for catalytic reactions. In the present report, we have grown a series of surface functionalized Cu x Co3 - x O4 nanostructures directly on a charge-collecting substrate (e.g., Ni Foam) using a straightforward electrochemical deposition process and investigated the effects of its surface functionalization, morphology, content of oxygen vacancies, electrochemically active surface area (ECSA), and electrical conductivity on the performance of water splitting.

(Invited) Surface Functionalized Copper-Cobalt Oxide Nanostructures for Efficient Water Splitting

The low-cost and low-toxic copper-cobalt oxide, CuCo2O4 have attracted a great deal of research interest owing to their wide range of applications such as oxygen evolution reaction, oxygen reduction reaction, hydrogen evolution reaction, alcohols oxidation, H2O2 decomposition, urea oxidation, and energy storage. Their controllable composition, electronic structure, valence states or redox characteristics, morphology, and high catalytic property have made them suitable as universal catalysts. However, their low intrinsic electrical conductivity still overshadows their practical application to some degree. In addition, The conventional preparation procedures of copper-cobalt oxide result in relatively low catalytic activity or large OER overpotential for catalytic reactions. In the present report, we have grown a series of surface functionalized Cu x Co3 - x O4 nanostructures directly on a charge-collecting substrate (e.g., Ni Foam) using a straightforward electrochemical deposition process and investigated the effects of its surface functionalization, morphology, content of oxygen vacancies, electrochemically active surface area (ECSA), and electrical conductivity on the performance of water splitting. Figure 1

Colossal dielectric and room temperature ferromagnetic response in CCoTO delafossite type nanostructure

Delafossite type CuCo0.5Ti0.5O2 (CCoTO) nanostructure has been synthesized via a low temperature modified chemical synthesis technique. X-ray diffractogram reveals the crystallinity and phases of synthesized CuCo0.5Ti0.5O2 nanomaterial, consisting of two polytype, 2H and 3R. Surface morphology and information about structure and phase of CuCo0.5Ti0.5O2 nanostructure has been studied by FESEM and HRTEM analysis. Thermal analysis shows the decomposition behavior and stability over the observed temperature range. On application of external electric field, CuCo0.5Ti0.5O2 nanostructures calcined at 250 °C and 400 °C attain a dielectric constant of ~41,000 and ~22,500 at 40 Hz frequency respectively which attains very good stability over 40 Hz to 1 MHz frequency range. Internal barrier layer capacitor (IBLC) model and impedance spectroscopy has been used to analyze the occurrence of giant dielectric response. From vibrating sample magnetometer (VSM) analysis it can be confirmed that, under the influence of external applied magnetic field at room temperature all the synthesized CuCo0.5Ti0.5O2 nanostructures are ferromagnetic in nature. Thus, the synthesized magneto-dielectric CCoTO nanostructure can be used in microstructure device, barrier layer capacitor, spinotronic device fabrication and also a promising candidate material for future many other electronic industrial applications.

Control sonochemical parameter to prepare pure Zn0.35Fe2.65O4 nanostructures and study their photocatalytic activity.

Zn0.35Fe2.65O4 nanostructure was prepared as a ferrite material by using a simple sonochemistry method. The effect of different parameters such as sonication time and power were studied. By increasing sonication power and time more Fe+3 ions reduced to Fe+2. This happens because H and OH radicals produced under sonication could act as a reduction agent. Therefore by increasing power and sonication time more Fe+3 ions reduced. Pure Zn0.35Fe2.65O4 nanostructure was formed when sonication time and power were 30 min and 40 W. Surface area for pure Zn0.35Fe2.65O4 nanostructure was 64 m2.g-1. Afterward, Zn0.35Fe2.65O4 nanostructures were applied to treat water containing different pollutants. As-prepared nanostructures degrade 60.8, 77.9, 55.2 and 44.0% of Acid Violet 7, Acid Blue 92, Acid Red 14, and Methyl Orange under visible light during 180 min irradiation. In addition, 94.5, 84.2, and 43.0% of AV7, PhR, and Ery were degraded under UV light during 120 min irradiation. The as-synthesized Zn0.35Fe2.65O4 nanostructure was characterized through the SEM, EDX, TEM, CV, DRS, BET, VSM, and XRD.

Combination of air-dispersion cathode with sacrificial iron anode generating Fe2+Fe3+2O4 nanostructures to degrade paracetamol under ultrasonic irradiation

In the present study, ultrasound (US) was coupled with an electrochemical process (ECP) consisting of a novel cathode of carbon cloth (CC)-carbon black (CB) as the nano-composite air-dispersion cathode (NADC) for the degradation of paracetamol (APAP) in an aquatic medium. The NADC favored in situ production of H2O2 by the cathodic reduction. The implementation of iron sacrificial anode instead of dimensionally stable anodes resulted in the generation of Fe2+Fe3+2O4 nanostructures in the solution. The Fe2+Fe3+2O4 nanostructures were activated by means of both US and H2O2 to produce more OH in the aqueous solution. In addition, the utilization of US caused the conversion of H2O2 to OH irrespective of free oxidizing radicals generated through cavitation phenomenon. The hybrid method based on coupling US and NADC-ECP in the presence of Fe2+Fe3+2O4 nanostructures proved synergism (39.8%) allowing to effective decomposition of APAP. The pulse mode of US enhanced the degradation efficiency of APAP as compared to the sweep and normal modes. The intermediates of the degradation route were identified using GC–MS analysis as well as mineralization efficiency. The toxicity assay was also performed based on the inhibition test using activated sludge of a biological wastewater treatment plant.

Anisotropic ferromagnetism in Fe x Sn1−x O2 nanostructure arrays

Periodic arrays of Fe x Sn1−x O2 nanostructures were fabricated by glancing angle sputter deposition onto self-assembled close-packed arrays of 200-nm-diameter polystyrene microspheres. After annealing at 873 K for 3 h, all the films were crystallized to rutile SnO2 and maintained good thermal stability in the morphology. Compared with Fe x Sn1−x O2 flat films, arrays of Fe x Sn1−x O2 nanostructures possessed larger saturation magnetic moment and exhibited both perpendicular and in-plane magnetic anisotropy, resulting from the anisotropic morphology of Fe x Sn1−x O2 nanostructures. The EPR signal originating from the oxygen vacancies significantly varied with the Fe concentration and reached the strongest at x = 0.059, which is consistent with the saturation magnetization. It demonstrates that the oxygen vacancies are an important factor for the ferromagnetism of Fe x Sn1−x O2 films.

Novel preparation of ultrafine MnCo1.75Fe0.25O4 nanostructures for the photodegradation of Acid Red 88

For the first time, ultrafine MnCo1.75Fe0.25O4 nanostructures were prepared via a novel coprecipitation–calcination route by using tetraethylenepentamine (tepa) and SDBS as precipitating agent and surfactant, respectively. Results of this study show that particle size and morphology of the MnCo1.75Fe0.25O4 samples can be controlled by setting main reaction parameters such as reaction temperature, surfactant type and calcination temperature. The as-prepared MnCo1.75Fe0.25O4 nanostructures were characterized by EDX, TEM, FESEM, VSM, FT-IR, XRD and UV–Vis analysis. The photocatalytic degradation of the acid red 88 dye as water pollutant was performed to examine the photocatalytic performance of as-prepared MnCo1.75Fe0.25O4 nanostructures.

Nickel Cobaltite Nanostructures for Photoelectric and Catalytic Applications.

Bimetallic oxide nickel cobaltite (NiCo2 O4 ) shows extensive potential for innovative photoelectronic and energetic materials owing to their distinctive physical and chemical properties. In this review, representative fabrications and applications of NiCo2 O4 nanostructures are outlined for photoelectronic conversion, catalysis, and energy storage, aiming to promote the development of NiCo2 O4 nanomaterials in these fields through an analysis and comparison of their diverse nanostructures. Firstly, a brief introduction of the spinel structures, properties, and morphologies of NiCo2 O4 nanomaterials are presented. Then, the advanced progress of NiCo2 O4 nanomaterials for both photoelectronic conversion and energy fields is summarized including such examples as solar cells, electrocatalysis, and lithium ion batteries. Finally, further prospects and promising developments of NiCo2 O4 nanomaterials in these significant fields are proposed.

Three-dimension hierarchical flower-like Ni1.5Co1.5O4 nanostructures composed of two-dimension ultrathin nanosheets as an anode material for lithium ion batteries

Uniform three-dimension hierarchical flower-like Ni1.5Co1.5O4 nanostructures were synthesized on a large scale by a simple, low-temperature hydrothermal method without any template, catalyst and surfactant, followed by a calcinating process. The obtained Ni1.5Co1.5O4 products were composed of two-dimension ultrathin nanosheets with random attachment. Nitrogen sorption isotherm shows that this structure possesses a high specific surface area of 118.8m2g−1 with an average pore diameter of 16.67nm. When tested as an anode material, the as-prepared Ni1.5Co1.5O4 nanostructures exhibit an initial discharge capacity of 1461.5mAhg−1. After 30 cycles at the current density of 100mAg−1, the discharge capacity still keeps 980.8mAhg−1. The obtained three-dimension hierarchical flower-like Ni1.5Co1.5O4 nanostructures show a promising anode material for lithium ion batteries.

Hydrothermal synthesis of 3D Cu0.45Mn0.55O2 nanostructures; lattice vibrations and novel photoluminescence properties

In this paper, Novel 3D Cu0.45Mn0.55O2 nanoarchitectures self-assembled by interconnecting densely stacked nanosheets have been successfully synthesized by facile hydrothermal growth method. The crystalline phase, morphology, particle size and component of the as-prepared nanomaterial were characterized by X-ray diffraction, field-emission scanning electron microscopy (FESEM) with energy-dispersive X-ray spectroscopy and Raman spectroscopy. FESEM analysis shows that the size of 3D Cu0.45Mn0.55O2 nanostructures is in the range of 1–1.5 μm, and the thickness of interconnected nanosheets is about 45 nm on the average. The structural features of as-synthesized Cu0.45Mn0.55O2 nanostructures are studied to analyze the near-neighbor environment of oxygen coordination around manganese and copper cations reported for the first time using Raman scattering spectroscopy. Moreover, the novel photoluminescence spectra of the as-prepared Cu0.45Mn0.55O2 nanostructures are reported exhibiting prominent emission bands located in red-violet spectral region.

Dual emissive Sn(1−2x) Cux Cox O2 nanostructures – A correlation study of doping concentration on structural, optical and electrical properties

A simplistic chemical co-precipitation route was adapted to synthesize Sn(1−2x) Cux Cox O2 (x=0, 0.01 and 0.03) nanoparticles. The structural studies were carried out using X-ray diffraction pattern and the shift in diffraction peak, lattice constant and particle size with doping concentration was determined. The morphology of nanoparticles with an average size of 13–18nm was observed using high-resolution transmission electron microscopy. A significant increase in the absorption edge with an increase in doping concentration was observed using ultraviolet-visible absorption spectroscopy. Further, the blue-shifted band gap value was plotted using Tauc’s relation. The near-band-edge emission at 3.9eV and the deep-level-emission at 2.4eV were systematically examined by photoluminescence spectroscopy. The dependence of doping concentration on temperature-reliant electrical conductivity was examined using DC electrical measurements. A meticulous exploration on diffraction peak shift, the Burstein-Moss shift, the mechanism for dual emission and the decreased electrical conductivity in Sn(1−2x) Cux Cox O2 nanostructures were further discussed.

LiNi0.5Mn1.5O4 nanostructures with two-phase intergrowth as enhanced cathodes for lithium-ion batteries

LiNi0.5Mn1.5O4 (LNMO) nanostructures (microspheres composed of nanoparticles) are prepared from urchin-like γ-MnO2 by calcinating under 800°C, the product shows Fd3m-based phase involving minor rock salt phase and Mn3+ ions confirmed by its Raman spectra, X-ray diffraction pattern and electrochemical activities. Furthermore, HRTEM images and EDS line-scanning spectroscopy patterns focusing on a single nanoparticle provide direct observation of intergrowth of two phases that minor P4332 phase is found on the edge of Fd3m body coupled with the varying Mn/Ni ratio. In comparison, the other sample is obtained by adding an annealing treatment at 700°C after calcinating at 800°C, which preserves the nanostructured architecture of C800 and displays all the structural characteristics of pure P4332 phase. As cathode materials for lithium-ion batteries, merely calcined sample receives discharge capacities of 91 mAh•g−1 even at 50C, and 100.5 mAh•g−1 after 300 cycles at 5C, which shows better combination of rate and cycling performances than its counterpart with pure P4332 phase.

Hydrothermal synthesis of Cu0.45Mn0.55O2 nanowhiskers: Structural characterizations and optical properties

We report the hydrothermal-growth of 3D flower-like Cu0.45Mn0.55O2 nanowhiskers self-assembled by interconnecting single-crystalline nanosheets. FESEM analysis shows that the size of Cu0.45Mn0.55O2 nanowhiskers is in the range of 1–2μm. Structural investigations reveal that the phase of Cu0.45Mn0.55O2 nanostructures is insensitive after exposure to electron beam irradiation. The novel photoluminescence spectra of the as-prepared nanograined Cu0.45Mn0.55O2 exhibit prominent emission bands located in green–violet spectral region. Ultraviolet–visible absorption spectrophotometry was used to determine the absorption behavior of Cu0.45Mn0.55O2 nanostructures and a direct optical band gap of 2.53eV was acquired by the Davis–Mott model.