Scalable synthesis of Sb(III)Sb(V)O4 nanorods from Sb2O5 powder via solvothermal processing

Scalable Sb(III)Sb(V)O₄ nanorods from Sb₂O₅ powder were prepared using solvothermal route. XRD and HRTEM demonstrate that the nanorods are single-crystal orthorhombic-Sb₂O₄ phase with several micrometers long and 200-300 nm diameter size. XPS result further shows that the antimony cations in the nanorods are composed of three valence and five valence antimony ions. The emission of the nanorods appears around 450 nm wavelength. The formation mechanism of the Sb(III)Sb(V)O₄ nanorods was discussed in detail.     

Plasmonics properties of trimetallic Al@Al2O3@Ag@Au and Al@Al2O3@AuAg nanostructures

Bimetallic and trimetallic nanoparticles have attracted significant attention in recent times due to their enhanced electrochemical and catalytic properties compared to monometallic nanoparticles. The numerical calculations using Mie theory has been carried out for three-layered metal nanoshell dielectric–metal–metal (DMM) system consisting of a particle with a dielectric core (Al@Al₂O₃), a middle metal Ag (Au) layer and an outer metal Au (Ag) shell. The results have been interpreted using plasmon hybridization theory. We have also prepared Al@Al₂O₃@Ag@Au and Al@Al₂O₃@AgAu triple-layered core–shell or alloy nanostructure by two-step laser ablation method and compared with calculated results. The synthesis involves temporal separations of Al, Ag, and Au deposition for step-by-step formation of triple-layered core–shell structure. To form Al@Ag nanoparticles, we ablated silver for 40 min in aluminium nanoparticle colloidal solution. As aluminium oxidizes easily in water to form alumina, the resulting structure is core–shell Al@Al₂O₃. The Al@Al₂O₃ particle acts as a seed for the incoming energetic silver particles for multilayered Al@Al₂O₃@Ag nanoparticles is formed. The silver target was then replaced by gold target and ablation was carried out for different ablation time using different laser energy for generation of Al@Al₂O₃@Ag@Au core–shell or Al@Al₂O₃@AgAu alloy. The formation of core–shell and alloy nanostructure was confirmed by UV–visible spectroscopy. The absorption spectra show shift in plasmon resonance peak of silver to gold in the range 400–520 nm with increasing ablation time suggesting formation of Ag–Au alloy in the presence of alumina particles in the solution.     

First-principle study of electronic structure and stability of Sn0.5Sb0.5O2

A theoretical study on Sb-doped SnO₂ has been carried out by means of periodic density functional theory (DFT) at generalized gradient approximation (GGA) level. Stability and conductivity analyses were performed based on the formation energy and electronic structures. The results show that Sn_0.5Sb_0.5O₂ solid solution is stable because the formation energy of Sn_0.5Sb_0.5O₂ is −0.06 eV. The calculated energy band structure and density of states showed that the band gap of SnO₂ narrowed due to the presence of the Sb impurity energy levels in the bottom of the conduction band, namely there is Sb 5s distribution of electronic states from the Fermi level to the bottom of conduction band after the doping of antimony. The studies provide a theoretical basis to the development and application of Sn_1−xSb_xO₂ solid solution electrode.     

AgSbSe2 and AgSb(S,Se)2 thin films for photovoltaic applications

Silver antimony selenide (AgSbSe₂) thin films were prepared by heating sequentially deposited multilayers of antimony sulphide (Sb₂S₃), silver selenide (Ag₂Se), selenium (Se) and silver (Ag). Sb₂S₃ thin film was prepared from a chemical bath containing SbCl₃ and Na₂S₂O₃, Ag₂Se from a solution containing AgNO₃ and Na₂SeSO₃ and Se thin films from an acidified solution of Na₂SeSO₃, at room temperature on glass substrates. Ag thin film was deposited by thermal evaporation. The annealing temperature was 350 °C in vacuum (10⁻³ Torr) for 1 h. X-ray diffraction analysis showed that the thin films formed were polycrystalline AgSbSe₂ or AgSb(S,Se)₂ depending on selenium content in the precursor films. Morphology and elemental analysis of these films were done using scanning electron microscopy and energy dispersive X-ray spectroscopy. Optical band gap was evaluated from the UV-visible absorption spectra of these films. Electrical characterizations were done using Hall effect and photocurrent measurements. A photovoltaic structure: glass/ITO/CdS/AgSbSe₂/Al was formed, in which CdS was deposited by chemical bath deposition. J-V characteristics of this structure showed V_oc = 435 mV and J_sc = 0.08 mA/cm² under illumination using a tungsten halogen lamp. Preparation of a photovoltaic structure using AgSbSe₂ as an absorber material by a non-toxic selenization process is achieved.     

Size‐Dependent Synthesis of Cu12Sb4S13 Nanocrystals with Bandgap Tunability

Copper antimony sulfide (CAS) is an attractive material with a suitable bandgap for sunlight absorption and a high absorption coefficient in solar cells. There are few works focused on the size‐controllable synthesis of CAS nanocrystals, and no work reports on the special character of bandgap tunability until now. Herein, high‐quality monodispersed tetrahedrite (Cu₁₂Sb₄S₁₃) nanocrystals are synthesized through a novel solution‐based method by using thiols as ligands. The as‐prepared Cu₁₂Sb₄S₁₃ nanocrystals have a narrow size distribution and wide size range from 2 to 16 nm, while their absorption band edges are continuously tunable from 620 to 780 nm. The quantum size effects with bandgap tunability of Cu₁₂Sb₄S₁₃ nanocrystals are observed for the first time.     

Electric double layer capacitor based on activated carbon electrode and biodegradable composite polymer electrolyte

A series of polymer electrolyte based on poly(vinyl alcohol), lithium perchlorate (LiClO₄), and antimony trioxide (Sb₂O₃) was prepared via solution casting technique with distilled water as solvent. The dielectric behavior study reveals the non-Debye properties of the polymer electrolytes. In frequency dependence conductivity measurement, dispersion at low frequency was due to the interfacial resistance and space charge polarization inside the polymer electrolytes. The linear sweep voltammetry has proven that the incorporation of Sb₂O₃ into polymer matrix increases the maximum operational potential region. Electric double-layer capacitors (EDLCs) based on activated carbon electrode assembled with solid polymer electrolyte and composite polymer electrolyte has been evaluated by cyclic voltammetry (CV) and galvanostatic charge–discharge technique. CV test disclosed rectangular shapes with slight distortion, and there is no evidence for any redox currents on both anodic and cathodic sweeps, which indicates the typical behavior of EDLC. Both EDLC cells demonstrate good cyclability throughout 200 cycles with specific capacitance retention more than 90 %.     

Oxy-combustion of coal in liquid-antimony-anode solid oxide fuel cell system

A novel system based on the indirect oxy-combustion of coal in a liquid Sb anode solid oxide fuel cell (SOFC) has been used to produce electricity for over 48?h. Pulverized anthracite was fed to the liquid-antimony-anode of the fuel cell, and a peak power density of 47?mW cm^?2 was reached at 1023?K and 35?mW cm^?2 at 973?K. The fuel cell was prepared using a porous stainless-steel tube as a support for an LSM cathode, antimony oxide (Sb₂O₃)/yittria stabilized zirconia (YSZ, Y_0.08Z_0.92O_1.96) composite electrolyte (membrane), while liquid antimony acted as the anode. Liquid antimony/antimony oxide served as the intermediate medium for coal oxidation producing mainly carbon dioxide, which evolved as a separate gas stream. The fuel cell will facilitate carbon capture process, and simultaneously convert the chemical energy of coal directly to electricity. The experiment showed that while the fabricated electrolyte was porous, it became dense during the actual operation, preventing nitrogen leakage into the Sb/C side and producing reasonable open circuit voltage. Analysis of the experimental EIS data illustrates that the Ohmic resistance was the primary loss mechanism in the system. It further suggests approaches to improve the design. Continuous operation of this coal fueled oxy-combustion/fuel cell system achieved an overall efficiency of 28.2% despite of its tiny scale. Simple technologies can be employed to scale up this system at relatively low cost of fabrication and materials.     

Studies on the sonochemical polymorphism of Sb2O3 on activated graphite for the electrochemical determination of imipramine

This work reports the simultaneous sonochemical activation of graphite and sonohydrolysis of antimony chloride (SbCl₃) in the alkaline medium. The experiments conducted by bath sonicator operated at 37 kHz of frequency and a maximum power of 150 W. The simple sonohydrolysis of SbCl₃ alone produced an orthorhombic phase of Sb₂O₃, whereas, it produced mixed phases of cubic and orthorhombic Sb₂O₃ when introduced with graphite. Herein, the activated graphite (aGR) provides the best support to the growth of cubic phase. This cubic Sb₂O₃ is grown only on the graphite basal planes, which confirmed by scanning electron microscope. Moreover, the phase changes have identified by the X-ray diffraction, Raman and X-ray photoelectron analysis. The prepared aGR-Sb₂O₃ composite has applied to the electroanalytical studies of anti-depressant drug imipramine (IMP). The results showed that aGR-Sb₂O₃ revealed better activity than Sb₂O₃; the reasons are discussed comprehensively. Furthermore, aGR-Sb₂O₃ exhibited comparable analytical results for the determination of IMP.     

Etude par effet Mössbauer de la structure hyperfine nucleaire de 121Sb dans Fe2O3α

Samples of α-Fe₂O₃ containing antimony impurities have been investigated with the ¹²¹Sb Mössbauer effect.The ¹²¹Sb⁵⁺ impurity parameters were compared with those recently obtained for ¹¹⁹Sn⁴⁺ in α-Fe₂O₃. The observed increase of the H(0) value may be related to the greater electronic population of the 5s-orbitals in the case of Sb⁵⁺ doping.     

A Subnanoscale Investigation of Sb Segregation at MnO/Ag Ceramic/Metal Interfaces

We have studied Sb segregation at MnO/Ag(Sb) ceramic/metal heterophase interfaces employing three-dimensional atom-probe (3DAP) microscopy. Specimens are prepared by the internal oxidation of Ag(Mn) alloys, leading to the formation of nanometer-size MnO precipitates within a Ag(Mn) matrix. Sb is introduced into the internally oxidized specimens with a vapor diffusion treatment. Appreciable Sb segregation is observed only after a subsequent segregation anneal is performed, and the measured interfacial excess of Sb at the MnO/Ag(Sb) interfaces, _Sb ^MnO/Ag, is determined directly. The temporal evolution of the MnO precipitates is followed for the different processing steps employed. It is shown that the concentration of silver within the MnO precipitates decreases from an initial value of 45–50 at.% Ag to less than 5 at.% Ag with increasing annealing time at the different processing temperatures. Thus the MnO precipitates form under paraequilibrium conditions and the precipitates inherit Ag from the matrix. With increasing aging time orthoequilibrium conditions prevail and the MnO precipitates reject the silver atoms they inherited from the matrix.     

Carrier concentration and shallow electron states in Sb-doped hydrothermally grown ZnO

In order to obtain p-type ZnO, the incorporation of group-V elements on oxygen sites has received lots of attention. Recently, the implantation of Sb+ ions into ZnO has been shown to lead to reduced n-type conduction. However, a compensating effect due to implantation damage could not be ruled out. Therefore, single-crystal ZnO has been hydrothermally grown with additional Sb₂O₃, Sb₂O₅, and K(SbO)C₄H₄O₆ in the solution. Schottky barrier contacts have been deposited onto the () face. Capacitance–voltage measurements and thermal admittance spectroscopy have been used for electrical characterization, and secondary ion mass spectrometry was used to measure the Sb content in the samples. Clearly, all samples exhibited n-type conduction. A competition between the incorporation of oxygen and antimony is suggested.     

The nature of antimony-enriched surface layer of Fe-Sb mixed oxides

Antimony segregation is a common feature in Fe-Sb mixed oxides, which have been widely applied as catalysts in selective oxidation and ammoxidation reactions. This paper attempts to shed a light on the cause of such a common feature and on the nature of the antimony-enriched surface layer over FeSbO₄ by means of XPS surface analysis. Single-phase FeSbO₄ samples prepared by different methods were studied, and the antimony in their surface layer is a mixture of both Sb⁵⁺ and Sb³⁺ rather than single Sb⁵⁺. Their surface composition is close to FeSb₂O₆, which could be described as (FeSbO₄)(Sb₂O₄)_δ, δ = 0.5, and it is not “Fe(II)Sb(V)₂O₆” as suggested in literature. Fe-Sb mixed oxides with Sb/Fe > 1 (mol/mol) are mixtures of FeSbO₄ and Sb₂O₄, and the surface of FeSbO₄ grains would be a layer of (FeSbO₄)(Sb₂O₄)_δ, δ ≥ 0.5. Fe-Sb mixed oxides with Sb/Fe < 1 are mixtures of FeSbO₄ and Fe₂O₃, and the surface of FeSbO₄ grains would be a layer of (FeSbO₄)(Sb₂O₄)_δ, δ ≤ 0.5, but the remaining Fe₂O₃ would be encapsulated by a layer of FeSbO₄.     

119Sn and121Sb Mössbauer studies of BaSn1−x Sb x O3 Perovskite system

The relations between the electrical characteristics of BaSn_1?x Sb _x O₃ perovskite system and the contents of BaO, Sb₂O₃ and silicate sintering agent were studied by X-ray diffraction analysis and Mössbauer spectroscopy. It was found that the electrical conductivity is related to the substitution of Sb³⁺ for Sn⁴⁺, the content of sintering agent and the phase constitutents in samples. BaSnO₃, Ba₃Sn₂O₇, Ba₂SnO₄ and SnO₂ phases might appear in different fractions when the contents of BaO change from 0.5 mole to 3.5 mole. In low antimony percentage condition, pentavalent Sb³⁺ ions inserted in Sn⁴⁺ sites and formed the donor center. In high antimony percentage (x≥0.20) condition, the existence of an insulating phase (BaSb₂O₆) was confirmed.     

Sonochemical preparation of antimony subiodide

The substantiated isolation of the antimony subiodide (Sb₃I) is presented for the first time. It has been prepared using elemental Sb and I in ethanol under ultrasonic irradiation at 323 K. Its composition was characterized using X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray analysis (EDAX). The scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM) investigations exhibit that the samples are made up of large quantity of nanoparticles with diameters smaller than 20 nm and single crystalline in nature. The interplanar spacings in Sb₃I that have been determined using powder X-ray diffraction (XRD), selected area electron diffraction (SAED) and HRTEM are very similar. Surprisingly, the registered XRD patterns are identical to the one reported earlier for Sb₄O₅I₂.     

Electron density distribution in BaPb<Subscript>1 − <Emphasis Type="Italic">x</Emphasis></Subscript>Sb<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>O<Subscript>3</Subscript> superconducting oxides studied by double nuclear magnetic resonance methods

The effect of charge disorder on the formation of an inhomogeneous state of the electron system in the conduction band in BaPb_{1 − x} Sb _x O₃ superconducting oxides is investigated experimentally by NMR methods. The NMR spectra of ¹⁷O are measured systematically, and the contributions from ¹⁷O atoms with different cation nearest surroundings are identified. It is found that microscopic regions with an elevated spin density of charge carriers are formed within two coordination spheres near antimony ions. Nuclei of the superconducting phase of the oxide (regions with an elevated antimony concentration) microscopically distributed over the sample are detected in compounds with x = 0.25 and 0.33. Experiments in which a double resonance signal of the spin echo of ¹⁷O-²⁰⁷Pb and ¹⁷O-¹²¹Sb are measured in the metal phase of BaPb_{1 − x} Sb _x O₃ oxides are carried out for the first time. The constants of indirect heteronuclear spin-spin ¹⁷O-²⁰⁷Pb interaction are determined as functions of the local Knight shift ₂₀₇ Ks. The estimates of the constants of the indirect interaction between the nuclei of the nearest neighbors (O-Pb and Pb-Pb atoms) and analysis of evolution of the NMR spectra of ¹⁷O upon a change in the antimony concentration are convincing evidence in favor of the development of a microscopically inhomogeneous state of the electron system in the metal phase of BaPb_{1 − x} Sb _x O₃ oxides.     

Photocatalytic properties of porous C-doped TiO2 and Ag/C-doped TiO2 nanomaterials by eggshell membrane templating

Porous organic carbon-doped titania (C-TiO₂) nanomaterials and their composites with Ag nanoparticles (Ag/C-TiO₂) were synthesized by an eggshell membrane templating method, and their structural and photocatalytic properties were systematically characterized. These nanomaterials, exhibiting a macroscopic morphology of a thin film, are composed of interwoven tubes, and the tube wall consists of nanocrystals. The doped organic carbon was composed of the active carbon and carbonate species, which could form a layer around the surface of TiO₂ nanoparticles, while the silver was incorporated into Ag/C-TiO₂ composites as separated Ag nanoparticles. The degradation of methylene blue under visible light irradiation was employed to evaluate the photocatalytic activity of these as-prepared TiO₂-based materials. Both C-TiO₂ and Ag/C-TiO₂ nanomaterials showed higher photocatalytic activity than pure TiO₂ material–commercial Degussa P25. These results can be accounted for the coupling effect of the incorporation of carbon species and Ag nanoparticles.     

Interaction of Sb ions with Eu ions during the room temperature synthesis of luminescent Sb2O3 nanorods: Probed through Eu luminescence

The interaction of Eu³⁺ with Sb³⁺ ions during the room temperature synthesis of luminescent Sb₂O₃ nanorods is investigated using luminescence and vibrational spectroscopic techniques. Our results demonstrate that well crystalline, oriented Sb₂O₃ nanorods having length of around 3-4 μm, a width of around 100-200 nm and luminescence at around 390 nm can be synthesized at room temperature. Incorporation of Eu³⁺ in these nanorods has been attempted and it is found that Eu³⁺ ions do not have any interaction with nanorods and their orientation. Detailed Eu³⁺ luminescence and XRD studies confirmed that a part of Sb³⁺ ions reacts with Eu³⁺ ions in the presence of hydroxyl ions (present in the medium) to form an amorphous antimony europium hydroxide compound. The amorphous compound on heating at high temperatures leads to its decomposition, giving hydrated Sb(V) oxides and Eu₂O₃ as major phases.     

Infrared-to-visible upconversion in Er and Er/Yb activated Sb2O4 nanopowders prepared by sol-gel route

We prepared Er³⁺ doped and Er³⁺/Yb³⁺ codoped Sb₂O₄ nanocrystals by the sol-gel method. The Raman, X-ray diffraction (XRD), transmission electron microscope (TEM), and photoluminescence spectra of the samples were studied. The phonon energy of the Sb₂O₄ nanocrystals is very low (the maximum value being 461 cm⁻¹). The upconversion (UC) red emission of the Er³⁺/Yb³⁺ codoped sample is very strong at 975 nm laser diode excitation. The Sb₂O₄ nanocrystals will be a promising luminous material.     

Heating of an Atomic Force Microscope tip by femtosecond laser pulses

During the 18th Egyptian dynasty (1570–1292 B.C.), opaque white, blue and turquoise glasses were opacified by calcium antimonate crystals dispersed in a vitreous matrix. The technological processes as well as the antimony sources used to manufacture these crystals remain unknown. Our results shed a new light on glassmaking history: contrary to what was thought, we demonstrate that Egyptian glassmakers did not use in situ crystallization but first synthesized calcium antimonate opacifiers, which do not exist in nature, and then added them to a glass. Furthermore, using transmission electron microscopy (TEM) for the first time in the study of Egyptian opaque glasses, we show that these opacifiers were nano-crystals. Prior to this research, such a process for glassmaking has not been suggested for any kind of ancient opaque glass production. Studying various preparation methods for calcium antimonate, we propose that Egyptian craftsmen could have produced Ca₂Sb₂O₇ by using mixtures of Sb₂O₃ or Sb₂O₅ with calcium carbonates (atomic ratio Sb/Ca=1) heat treated between 1000 and 1100°C. We developed an original strategy focused on the investigation of the crystals and the vitreous matrices using an appropriate suite of high-sensitivity and high-resolution micro- and nano-analytical techniques (scanning electron microscopy (SEM), X-ray diffraction (XRD), TEM). Synchrotron-based micro X-ray absorption near edge spectroscopy (μ-XANES) proved to be very well suited to the selective measure of the antimony oxidation state in the vitreous matrix. This work is the starting point for a complete reassessment not only of ancient Egyptian glass studies but more generally of high-temperature technologies used throughout antiquity.     

Characterization of microcrystals in some ancient glass beads from china by means of confocal Raman microspectroscopy

A total of ten ancient colored glass beads were analyzed by confocal Raman microspectroscopy for the non‐destructive identification of microcrystals within them. These beads were excavated from different regions of China, including Xinjiang, Henan, Hubei and Guangxi Provinces, and were dated mainly from the 10^th century BC to the 9^th century AD. For the first time, either tin or antimony‐based opacifiers/colorants including calcium antimonate (CaSb₂O₆, Ca₂Sb₂O₇), bindheimite (Pb₂Sb₂O₇), lead tin yellow type II (PbSn_1‐xSi_xO₃) and cassiterite (SnO₂) were identified in nine samples. In addition, other crystalline phases such as cuprite (Cu₂O), α‐wollastonite (CaSiO₃), diopside (CaMgSi₂O₆), feldspar (KAlSi₃O₈), calcite (CaCO₃) and quartz (SiO₂) were also detected. Another interesting phenomenon first observed in this study was the coexistence of Sn‐ and Sb‐based opacifiers/colorants in one mosaic bead from Guangxi. The possibility to use Sb‐ and Sn‐based opacifiers/colorants for dating and provenance study of ancient glass found in China is discussed briefly. Copyright © 2013 John Wiley & Sons, Ltd.