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The possible exhaustion of fossil fuels in the near future and soaring global energy demand have driven the search for new types of sustainable and renewable alternatives. Perovskite (CHNHPbX, X = I, Br, Cl) solar cells are a type of solar cell based on a perovskite absorber, most commonly a tin halide-based or hybrid organic-inorganic lead material, as the visible-light sensitizer layer, which produces electricity from sunlight. Recently, perovskite solar cells have received substantial worldwide attention. Compared with traditional solar cells, the perovskite solar cells can obtain high efficiency with a simple architecture and via a cost-effective process. In the latest 5 years, the efficiency of perovskite solar cells to convert power has skyrocketed from 3.8 % to more than 19.3 %. It is the fastest advancing solar technology to date. The highest efficiency demonstrated by perovskite solar cells is higher than that of dye-sensitized solar cells (DSSCs). A lager number of research groups have demonstrated that perovskite solar cells may ultimately boost efficiency as high as 25 %. The high efficiency and cheap production costs make it evident that perovskite solar cells have great potential to be commercialized soon. In this review, the history, materials, processing and architecture of solar cells are discussed to obtain a better understanding of high-performance perovskite solar cells. [ABSTRACT FROM AUTHOR]

We report a mild template-free hydrothermal route for selective synthesis of SnO2 hollow microspheres and nano-sheets using SnCl2 and NaOH as initial materials. By switching the solvent from water to ethanol, the formed SnO2 nanostructures changed from nano-sheets to hollow microspheres. The obtained nano-sheets were single crystalline in structure. On the basis of the characterization of intermediate products, the formation of SnO2 hollow microspheres was ascribed to a crystal growth process, while the formation of SnO2 nano-sheets was ascribed to the oxidation of SnO2 sheets during the hydrothermal process. Further characterization of the SnO2 hollow microspheres and nano-sheets by X-ray photoelectron spectroscopy and UV-Vis absorption spectroscopy reveals different optical absorption properties and valence band electronic structures. In addition, the SnO2 nano-sheets and hollow microspheres exhibit different sensing properties. The present work provides a facile and simple template-free method for the synthesis of nano-structured SnO2. [ABSTRACT FROM AUTHOR]

Abstract: Square SnO2 nano-sheets have been successfully synthesized by a template-free hydrothermal method basing on the reaction between SnCl2 and NaOH in ethanol/water solution. The products have been characterized by X-ray diffraction, scanning electron microscope, and transmission electron microscope. The size and morphology of nano-sheets could be controlled by changing the ratio of ethanol to water. Compared experiments showed that the addition of NaOH was crucial to the formation of SnO2 nano-sheets, and the addition of glycol could induce the formation of cabbage-like structure. The nano-sheets show a strong absorption peak around 330 nm, corresponding to a band gap value of 3.75 eV. This blue shift of the band gap energy was possibly induced by the spatial confinement of excitons in the nano-sheet structures. [Copyright &y& Elsevier]

• The offset characteristics of HTS wireless power transfer (WPT) system was investigated systematically. • The transfer efficiency decreases monotonically with the increase of offset distance. A "flat top" exists in transfer efficiency at short-range radial offset, benefiting the practical applications. • The relationship between load receiving power (LRP) and offset distance is not monotonic. There is an optimal position to reach corresponding maximum LRP. • The HTS WPT system exhibits superior performance in both transfer efficiency and LRP than the copper WPT system. The usage of high-temperature superconducting (HTS) coils in magnetically-coupled resonant wireless power transfer (WPT) systems can considerably improve the transfer efficiency, and hence it attacked great attention. However, there are few studies on offset characteristics in HTS WPT systems. In order to further improve the performance of HTS WPT systems, we have studied experimentally the influences of relative displacement of the coils on the transfer efficiency and load receiving power (LRP) in a magnetically-coupled resonant WPT system. The WPT systems using copper coils and HTS coils were carefully compared. The results show that the transfer efficiency decreases monotonically with the increasing offset. However, there is an optimal position for the LRP to achieve the maximum value. Both the transfer efficiency and LRP of the HTS WPT system are higher than those of the copper WPT system under the same conditions. [ABSTRACT FROM AUTHOR]

The perovskite membrane with large particle size, uniform coverage and high quality is the prerequisite for the preparation of efficient and stable perovskite solar cells. Various additives have been used to increase the grain size and improve the film morphology and crystal quality. In this paper, methylammonium chloride (MACl) was proposed to obtain high crystalline quality of ( FAPbI 3) 0. 8 5 ( MAPbBr 3) 0. 1 5 perovskite absorption layer. The results show that the adding ammonium methyl chloride into the precursor of tricationic perovskite not only passivates surface defects to form high-quality and large-grain perovskite films, but also facilitates the formation of pure α -phase FAPbI 3 . Meanwhile, the designed perovskite precursor solutions were used to fabricate mesoporous perovskite solar cells (PSCs). Owing to the perovskite layer consisting of optimized MACl doping, the short-circuit current density (J sc ) of PSCs reaches 23.81 mA/cm2, which is 2.73 mA/cm2 higher than the primary ( FAPbI 3) 0. 8 5 ( MAPbBr 3) 0. 1 5 based on PSCs. The obtained power conversion efficiency (PCE) increases from 13.67% to 17.59%. [ABSTRACT FROM AUTHOR]

The width of REBCO (REBa2Cu3O7-x, RE: rare earths)-coated conductor is an important factor associated with AC (alternating current) loss of the tape. In the same electromagnetic environment, coils winding with narrow REBCO tapes generate less AC loss than the wide one. For a single coil, the critical current density of outer turns is higher than that of inner turns, due to the inhomogeneous distribution of magnetic field. This paper presents a multi-width technique which is applicable for single REBCO coil by partly slitting single tape in place, which can effectively reduce AC loss, while maintaining current-carrying capacity in high field. The AC loss of coils with slitting in different turns is calculated by the software of finite element modeling (FEM). The results indicate that the appropriate slitting in radially outer turns of coil appears effective to reduce AC loss, especially in the case of the coils running with high current. [ABSTRACT FROM AUTHOR]

The present work reports our efforts to enhance the performance and uniformity for the long tapes of metal–organic deposition YBa2Cu3O7−x (MOD-YBCO) layer on ion-beam-assisted deposition MgO (IBAD-MgO) template. Reflection High-energy electron diffraction (RHEED) is employed to realize the in-situ growth monitor of IBAD-MgO, as well as the correlation between the quantitative RHEED peaks and in-plane texture of Epi-MgO identified by XRD, which is an effective guide to improve the uniformity and performance of long YBCO tapes. In addition, the surface of the LMO layer during the magnetron sputtering process is improved via controlling the O2 flux, and then the critical-current density (Jc) of YBCO films has been improved. By optimizing the texture of the MgO layer and precisely controlling the LMO layer growth conditions, the performance and uniformity of YBCO-coated conductors grown by metal–organic deposition (MOD) have been greatly enhanced. The superconducting current-carrying capacities of 12-mm-wide tapes have upgraded steadily from 400–500 A to 500–550 A in past 3 years. The laminated CC tapes with current-carrying capacities of 150–170 A per 4-mm width show good uniformity and high quality along 500-m length, implying being promising for various commercial power applications. [ABSTRACT FROM AUTHOR]

The joint-free superconducting annular disks and their stacks, obtained by cutting REBCO (REBa2Cu3O7–δ, RE: rare earth) wide tapes, are proposed as promising passive magnetic shields in this paper. The shielding properties of the disks have been numerically studied using the finite element method. The shielding factor (SF), defined as the ratio between the applied field and the central field, had a frequency-independent value when the magnetic field is much lower than the full penetration field. It appears to have a linear relationship with the ratio of the outer and inner diameter of the disk. Furthermore, various architectures with stacked disks were studied. High shielding factors (SF > 104) under enhanced full penetration fields of above 100 mT can be obtained in the configuration of more disks and proper disk distance (the distance between the disks on each layer). Two stacked disks were designed. In a 1-mT, 1-Hz applied field, the SF of the 4-mm inner diameter discrete stack is 1.21 × 107 (140 dB), and the SF of the 20-mm inner diameter split stack reaches 3.44 × 104 (90 dB). It implies that the stacked REBCO disks have great potential for the application of high-efficiency magnetic shielding. [ABSTRACT FROM AUTHOR]

The screening current induced in superconductors can passively shield external magnetic fields and hence provide a noise free environment for precision sensors and instruments. This paper presents a novel design employing artificial joint-free REBCO (REBa2Cu3O7-x, RE: rare earths) coils which can economically extend the field shielding space for larger instruments, e.g. clinical equipment. We compared the shielding factors of single, double and multi-coils, and confirmed a coil with Helmholtz construction as the optimal architecture. Due to the zero resistance of the joint-free REBCO coils, the shielding effectiveness reaches 80 dB at the center of coils, shielding 99.99% of the external magnetic field of 10 μT at 1 × 10−5 Hz, and 40 dB (99%) in a greater spherical space of 40 mm in diameter. Additionally, the shielding effectiveness does not decrease in the external magnetic field of 1 nT. Such a low frequency magnetic shielding effect implies promising applications for the present work, such as preventing interference magnetic fields from precision instruments, which generally require field sensitivity as low as the fT · Hz−1/2 range. [ABSTRACT FROM AUTHOR]

LaMnO3−δ (LMO) films with different oxygen contents are deposited on Epi-MgO/IBAD-MgO templates using reactive magnetron sputtering under varying temperatures and atmospheres. Subsequent YBa2Cu3O7−δ (YBCO) films are grown on LMO layers by metal-organic deposition (MOD) method. X-ray diffraction measurements reveal that YBCO texture cannot be further improved when the full width at half maximum (FWHM) values of LMO (011) φ-scans (evaluation on in-plane alignment) and LMO (002) ω-scans (evaluation on out-of-plane alignment) for LMO films are less than 8° and 4°, respectively. Sharp orientation with in-plane FWHM value of <3° for YBCO (103) φ-scan and out-of-plane FWHM value of <1.5° for YBCO (006) ω-scan can typically be achieved in YBCO films. Precise control of growth conditions, especially atmosphere, remains a feasible way to modify the surface of LMO films. It induces changes in oxygen content, lattice structure and surface morphology of LMO, and further affects the epitaxial growth of superconducting layers. Oxygen-deficient LMO with expanded lattice parameters and flat surface can effectively suppress the non-c-axis oriented YBCO, thereby enhancing the current carrying capability. The 500 m long YBCO coated conductors with conditioned LMO layers have an inductive critical current (Ic) ranging from 358 to 437 A/12 mm width with an average value of 398 A/12 mm width. [ABSTRACT FROM AUTHOR]

Polyethyleneimine (PEI) with an amount of -NH2 groups used in precursor solution could effectively reduce Cu2+ volatilization during the pyrolysis process. Thermogravimetric analysis shows that the temperature window of low-temperature pyrolysis for precursor solution with PEI (PEI-YBCO) is widened significantly. The slower pyrolysis process can enrich Cu2+ and improve critical current density (Jc) of PEI-YBCO films. The highest Jc is 3.03 MA/cm2 at 77 K when the amount of PEI is 0.5 g/10 mL and the film thickness is 400 nm. Then the thickness increases from 0.4 to 2.0 μm by changing the coating times. The Jc values of PEI-YBCO films decrease gradually with the thickness increase. However, the critical current (Ic) can be up to 197 A/cm (at 77 K, self-field) and Jc can still keep 1.68 MA/cm2 at 1.2 μm. [ABSTRACT FROM AUTHOR]

Bilayered YDy0.5Ba2Cu3.6O7−δ superconducting films with a thickness of about 1 μ were deposited by metallorganic deposition method, an interlayer of secondary phase of SrZrO3 (SZO) and BaZrO3 (BZO) were inserted. Detailed growth mechanism studies of these structures as well as superconducting properties in different temperatures and magnetic field range (0-5 T) were investigated. Structural analysis showed that bilayer structure changed clearly the growth mechanism of YBCO. The SZO interlayer smoothens the film surface. Magnetic measurements of superconducting properties demonstrated that the critical temperature decreases slightly when both of SZO and BZO interlayer were inserted. This indicates a growing strain effect at the layer interfaces. The critical current densities as well as pining forces of bilayered YDy0.5Ba2Cu3.6O7−δ in the entire applied temperature and magnetic field range were enhanced by the insertion of SZO layer and decreased when BZO layer is introduced. The enhancement of the pinning properties is explained by the dense flux pinning in layered YDyBCO superconductors; this result may give further improvements in the current-carrying capability. [ABSTRACT FROM AUTHOR]

Substrate engineering is very significant in the synthesis of the high-temperature superconductor (HTS) coated conductor. Here we design and synthesize several distinct and stable Cerium oxide (CeO 2 ) surface reconstructions which are used to grow epitaxial films of the HTS YBa 2 Cu 3 O 7-δ (YBCO). To identify the influence of annealing and post-annealing surroundings on the nature of nucleation centers, including Ar/5%H 2 , humid Ar/5%H 2 and O 2 in high temperature annealing process, we study the well-controlled structure, surface morphology, crystal constants and surface redox processes of the ceria buffers by using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and field-emission scanning electronic microscopy (FE-SEM), respectively. The ceria film post-annealed under humid Ar/5%H 2 gas shows the best buffer layer properties. Furthermore, the film absorbs more oxygen ions, which appears to contribute to oxygenation of superconductor film. The film is well-suited for ceria model studies as well as a perfect substitute for CeO 2 bulk material. [ABSTRACT FROM AUTHOR]

An effective soldering process of second-generation coated conductors (CCs) with low joint resistance was presented by using home-made equipment in the present study. The benefit of preprocessing, i.e., polishing, was proved with respect to the reduced joint resistances based on the voltage–current curves. It is revealed that the joint resistance of 10-8 Ω with an overlapping length as short as 2 cm can be achieved, while the joint resistances would further decrease with increasing the overlapping area, in agreement with Ohm's law. In the case of the overlapping length of 8 cm, the order of nΩ can be achieved for the resistances of solder joints. The heating time in joint fabrication process can be shortened to 1 min without negative effects on joint resistance, speeding up the soldering process largely. The effectiveness was evidenced further by the hard degradation in Ic through the joint part of the studied tapes and the enhanced adhesion between solder layer and Cu layer according to the cross-section observation. Temperature dependence of the joint specimen resistances suggested that the lattice constant of superconducting layer after jointing may be preferable to attain a higher critical temperature than that of original tape. The fragmentation of the superconducting layer and decohesion of the interface between hastelloy/buffer and ceramic layers, not the Cu-solder interface for the joint by external force, implied that the valid soldering was achieved using the present process. [ABSTRACT FROM PUBLISHER]

Oxygenation is one of the most essential processes for practical applications of REBa 2 Cu 3 O 7−δ (RE123, RE = Y, Gd etc. rare earths) superconductors. Second generation high-T c superconducting coated conductors are based on biaxial textured RE123 thin films, on which, a cover layer of silver for protecting is normally applied. It results in a little more complicated oxygenation process compared to naked film without silver protective layer. In the present work, a series of absorbing oxygen post-annealing processes were carried out for YBa 2 Cu 3 O 7−δ coated conductors. The oxygen diffusion procedure and the kinetics in the annealing process were investigated. Analysis and calculations show that the activation energy was 1.01 eV, consistent with previous reports. Moreover, experiments show that the “over-doping” phenomena frequently occurs in coated conductors, and thus dropping the T c to as low as 86–88 K. To improve the temperature margin for practical applications (temperature difference between the superconducting transition temperature T c and application temperature), we investigated the potential of increase in T c by preventing from the “over-doped” happening, while keeping oxygen in order. Finally, by employing the new annealing process, we can produce long (several hundred meters) coated conductor with high T c,onset (92 K), narrow transition width and stable performance. [ABSTRACT FROM AUTHOR]

The influence of various gas flow conditions on the nucleation and growth rate of YBa 2 Cu 3 O 7-δ (YBCO) coated conductors in the high-temperature heat treatment stage of low fluorine chemical solution deposition (LF–MOD) process have been investigated, including the gas flow rate and gas flow direction. The results indicated that film-growth rate is faster while a -axis oriented phase coexisted with c -axis in the films at the higher gas flow rate. And YBCO ( 00 l) grains grew slowly while a -axis oriented phase also nucleated easily on the end of the long films along gas flow direction. It could be caused by large quantities of HF gas accumulating from the chemical reaction for converting YBCO phase. Hence, the crystal mechanism of various LF–MOD methods can be supposed as still “BaF 2 ” process as the TFA-MOD method, and orientation nucleation and growth rate of YBCO films can be artificial control by adjusting the gas flow conditions. [ABSTRACT FROM AUTHOR]

BaHfO (BHO) has been proposed as a new cap layer material for YBaCuO (YBCO) coated conductors. Highly c-axis oriented BHO cap layer has been deposited on ion-beam assisted deposition-MgO buffered Hastelloy tapes by direct-current-magnetron sputtering method. The epi-growth of BHO films combined with its properties is investigated in details. The degenerated cubic crystal structure of BHO film is confirmed by Raman spectrum analysis. XRD θ-2θ scan, φ-scan and ω-scan reveal an excellent c-axis alignment with good in-plane and out-of-plane textures for BHO cap layers. SEM and AFM investigations show BHO cap layer a dense and crack-free morphology. Subsequently pure c-axis orientation YBCO film was epitaxial grown on such BHO cap layer successfully, shown BaHfO a potential cap layer material for coated conductors. [ABSTRACT FROM AUTHOR]

Thick YBaCuO (YBCO) films grown by metallorganic deposition (MOD) are very significant for high-performance superconducting wires. In the present work, the modified MOD method with reduced fluorine content in precursor solution (namely LF-MOD in the following) is applied to prepare the YBCO films with the purpose of reducing the processing time as well as increasing thickness. Five-layer YBCO films with a thickness of more than 2.5 μm are achieved after the effect of high-temperature annealing time ( t) on the morphology and texture of YBCO films is systematically investigated. It is suggested that an annealing time as long as 6 h appears necessary to achieve a good performance for such a thick YBCO film. To understand the evolution of texture with thickness, plasma etching is employed to characterize the profile morphology at different depths inside the films, revealing the a-axis grains together with the impurity phases arising from the incomplete reaction mostly present at the top surface only. [ABSTRACT FROM AUTHOR]

This work presents a study of the evolution of the phases in the intermediate heat treatment process (IHP) which was after the pyrolysis process and before the crystallization of YBCO superconducting thin films. It was shown that the evolution of the solid solution could always take place whether with or without water vapor and oxygen. When water vapor is present in the atmosphere, the evolution temperature of the intermediate phase was lower than the one without vapor. The intermediate phase of YCuO with the vapor was observed at 680 °C. By calculating the changes of Gibbs free energy of reactions possibly involved in the IHP, the priority reaction with water vapor was CuF>YF>BaF when CuF, YF, and BaF coexisted while CuF and YF prefer to react with BaO to form BaF while they coexisted. The appearance of intermediate phase features could be illustrated through the calculation. [ABSTRACT FROM AUTHOR]

Structural design and regulation of absorption capacity play important roles for improving energy storage performance of bimetallic oxides in supercapacitors (SCs). Herein, three-dimensional Co 3 -x Mn x O 4 (0 < x < 3) with different Co/Mn molar ratios are synthesized by hydrothermal method. Scanning electron microscopy (SEM) demonstrates the changes of the morphology of Co 3 -x Mn x O 4 (0 < x < 3) with different Co/Mn molar ratios, in which the Co 3 -x Mn x O 4 (x = 1.09) exhibits a hairly hydrangea-like morphology and thus provides a reduced contact resistance and an effective ion transition ability proved by the electrochemical measurements. Meanwhile, by theoretical calculations we prove that the addition of Mn adequately improves the absorption capacity of OH−on Co 3 -x Mn x O 4 and thereby boosts the reaction activity. Therefore, when the Co 3 -x Mn x O 4 (x = 1.09) is used as a SCs electrode, it performs a high specific capacitance of 326 F g−1 at a current density of 1 A g−1. Moreover, an assembled asymmetric supercapacitor (Co 3 -x Mn x O 4 (x = 1.09)@NF//AC@NF) demonstrates enhanced performances, such as an energy density of 17.77 Wh Kg−1 at a power density of 400 W Kg−1, an outstanding cycling stability with 83.3% retention over 10,000 cycles at a current density of 2 A g−1 and so on. Related studies indicate the potential applications of Co 3 -x Mn x O 4 in the future smart micro/nano energy storage devices. • A hairly hydrangea-like Co 3− x Mn x O 4 (x = 1.09) was synthesized successfully. • Theoretical calculations proved that the addition of Mn adequately improves the absorption capacity of OH− on Co 3− x Mn x O 4. • Specific capacitance of 326 F g−1 was performed at a current density of 1 A g−1. • Energy density of 17.77 Wh Kg−1 was reached at a power density of 400 W Kg−1. • 83.3% of specific capacitance was retained after 10,000 cycles at a current density of 2 A g−1. [ABSTRACT FROM AUTHOR]

Y 1– x Gd x Ba 2 Cu 3 O 7–δ -Ag ( x = 0, 0.25, 0.5, 0.75, 1) thin films were prepared on oxide buffered Hastelloy substrates by low fluorine metalorganic depostion (MOD) process. The effects of co-doping of Ag and Gd on the microstructures and superconducting properties of YBCO thin films are investigated with respect to improvement on texture and superconducting performance in case of optimized doping content. It is found that optimum addition of Ag and Gd may lead to better c -axis orientation, superior surface microstructure and finally give rise to much improvement of superconducting performance. [ABSTRACT FROM AUTHOR]

Comparing with conventional physical vapor deposition methods, electrochemistry deposition technique shows a crack suppression effect by which the thickness of CeO 2 films on Ni–5 at.%W substrate can reach a high value up to 200 nm without any cracks, make it a potential single buffer layer for coated conductor. In the present work, the processes of CeO 2 film deposited by electrochemistry method are detailed investigated. A hydroxide reactive mechanism and an oxide reactive mechanism are distinguished for dimethyl sulfoxide and aqueous solution, respectively. Before heat treatment to achieve the required bi-axial texture performance of buffer layers, the precursor CeO 2 films are identified in nanometer scales. The crack suppression for electrochemistry deposited CeO 2 films is believed to be attributed to the nano-effects of the precursors. [ABSTRACT FROM AUTHOR]

Bilayer buffer architecture of Gd 2 Zr 2 O 7 (GZO)/Y 2 O 3 was prepared on the biaxially textured tape of Ni–5 at% W (NiW) by reactive sputtering deposition technique. The buffer layer of GZO films were deposited with different thicknesses on Y 2 O 3 seeding layer with a given thickness of 20 nm. According to the results of φ-scan, the in-plane FWHMs of GZO films decreased and then reversed with increasing thickness of GZO, which corresponded with the in-plane FWHMs and superconducting properties of YBa 2 Cu 3 O 7− δ (YBCO) films. Reflection High-Energy Electron Diffraction (RHEED) was carried out to examine the surface texture of GZO films and the deteriorated surface alignment was found for thicker films. The thickness effect of GZO on performance of YBCO is the coupling result of surface texture and blocking effect caused by thickness. With the balance of these two factors, the YBCO/GZO(120 nm)/Y 2 O 3 /NiW architecture exhibit relatively high performance with the transition temperature T c of 92 K, a transition width Δ T c below 1 K, and a critical current density J c of 0.65 MA/cm 2 . [ABSTRACT FROM AUTHOR]

• The frequency characteristics of the HTS wireless power transmission (WPT) system was investigated systematically. • The peak of the maximum output power of the HTS-Cu WPT system will appear at a low frequency. • The use of HTS coils instead of copper coils could significantly improve the transmission efficiency and load reception power of WPT systems in the low-frequency range. Wireless power transmission (WPT) based on magnetically coupled resonance technology, providing high power energy transmissions at longer distances, is promising for practical applications such as the charging of electric vehicles. The traditional WPT system needs to operate at high frequencies to keep efficient energy transmission, and as a result, it requires a high-frequency AC power supplement where pronounceable energy losses may arise from. In the present paper, a high-temperature superconducting (HTS) WPT system is proposed to enable efficient energy transfer at low operating frequencies. The maximum output power and transmission efficiency of HTS-Cu and Cu-Cu WPT systems were compared experimentally with operating frequencies from 33 kHz to 342 kHz. The results show that the usage of the HTS-Cu WPT system can significantly improve the maximum transmission efficiency as well as the output power, especially at low operating frequencies. This provides a method for high-power WPT applications in the low-frequency range. [ABSTRACT FROM AUTHOR]

Abstract: We report the synthesis of barium phosphate (BP) nano-flake and its adsorption behavior to methyl blue (MB) in aqueous solution. The as-obtained BP nano-flake revealed pure rhombohedral crystal structure. The adsorption capacity of MB onto BP reached 1500mgg−1. The adsorption equilibrium results fitted well with the Freundlich isotherm model. The adsorption process took less than 30min to reach equilibrium. The adsorption kinetics was elucidated by the pseudo-second-order kinetic equation. It followed 2-stage and 3-stage intra-particle diffusion models for the low and high concentration of dye solutions, respectively. The adsorption of MB using the BP nano-flake was highly selective, compared with the adsorption of other dyes. The interactions between MB and BP were mainly the ionic interaction and hydrogen bonds, which were confirmed by the X-ray photoelectron spectroscopic results and the density functional theory calculations. The BP nano-flake revealed less than 5% decrease in adsorption amount when it was recycled and reused five times. The present work shows that the BP nano-flake is promising for practical applications in MB removal from aqueous solutions. [Copyright &y& Elsevier]

Abstract: This paper describes the preparation of nano-composite W–La2O3 material by freeze-drying and spark plasma sintering (SPS). The thermionic electron emission capability and surface properties of this material have been investigated. The surface compositions and depth profiles of the prepared material were checked “in situ” by means of AES from 298K to 1573K. Nano-composite W–La2O3 material exhibits good electron emission performance: a saturated emission current density of 1.46Acm−2 can be reached at 1673K with a corresponding work function of 2.79eV. The surface analysis results showed that the good emission capability might be related to an about 10nm surface layer contained excess La caused by diffusion of La from bulk material to the surface. [Copyright &y& Elsevier]

Abstract: Sn2O3-based NO gas sensors were fabricated and investigated in this study. The sensor doped by 1.0at.% antimony had a maximal response to NO gas at 473K. The NO gas with a concentration down to 10ppm can be detected by the sensor without any cross sensitivity to the interfering species such as NO2 and CO. The response speed was shortened about 5.7 times after mixing the 10.0wt.% SnO2 nanoparticles into the 1.0at.% Sn2O3:Sb gas sensor, which was resulted from the formation of Sn2O3–SnO2 hetero-junction. This kind of mixed-oxides gas sensor showed good response to NO gas, weak response to NO2 gas and unstable response to CO gas. [Copyright &y& Elsevier]

It is demonstrated that electrodeposition is a promising cost-effective technique to grow oxide buffer on metallic tapes. The resultant layer of CeO2 shows the biaxial texture of FWHM = 5.5° as well as a smooth surface of RMS = 2.0 nm, and YBa2Cu3O7−δ coated conductor with such a buffer exhibits the critical current density of 1.85 MA cm−2 at 77 K. Of more interest is that the CeO2 film thickness reaches a high value of more than 200 nm without any cracks, while it is very hard to achieve a thickness of more than 70 nm in the conventional vapor deposition methods employed. [ABSTRACT FROM AUTHOR]