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Supported gold catalysts have drawn great attention for many decades due to their outstanding performance in remedying the environment from carbon monoxide (CO) pollution. In this study, due to the large surface area of spongy Fe2O3, fabricated by salt-assisted ultrasonic spray pyrolysis, a considerable amount of Au was loaded on spongy Fe2O3 compared to low-surface-area non-spongy Fe2O3. It is seen that the spongy Fe2O3 catalyst loaded with Au has an interface that can be extremely active for CO desorption and O2 activation. That means it has high catalytic activity in CO oxidation than non-spongy and low surface area Fe2O3 loaded with Au. Also, the incorporation of Au in low alkaline condition further enhances the interaction between Au and Fe2O3, providing more active sites. This made the catalyst to have better activity, good stability over 60 hrs, and there was no carbonate on its surface. It had full conversion at 30 oC on 120 L g-1 h-1 with high TOF (2.2 s-1).

Double-perovskite PrBaCo2O5.5+δ thin films were grown on (001) LaAlO3 substrates for investigating the processing dynamic-tuned epitaxial nature and physical properties under different oxygen conte...

Arsenic (As) and cadmium (Cd) accumulation in rice is a great food safety concern. Simultaneous control of As and Cd accumulation in rice grown in co-contaminated rice paddies is highly desirable but difficult to achieve. Silicon oxide nanoparticles (SiO2 NPs) were shown to lower plant As and Cd accumulation in rice tissues separately, raising the possibility that SiO2 NPs may concurrently decrease both As and Cd in rice tissues in a co-contaminated soil. Due to the remarkable effect of water management, this study aimed at investigating the effects of SiO2 NPs on the uptake of As and Cd by rice seedlings under both continuous flooding (CF) and alternate wetting and drying (AWD) conditions. Pot experiments were conducted by exposing rice seedlings to soils containing 5 mg/kg As and 1 mg/kg Cd, and 0, 150, 500 or 2,000 mg/kg of SiO2 NPs for 14 days. SiO2 NPs displayed significant impact on plant As and Cd uptake and the net effect depended on the concentration of SiO2 NPs and water management schemes. Significantly, simultaneous reduction of As and Cd in rice shoots was observed at 500 mg/kg SiO2 NPs under AWD irrigation, in which SiO2 NPs reduced As and Cd in rice shoots by 29% and 68%, respectively, compared with seedlings exposed to As and Cd only at the same irrigation condition. Rice shoots contained approximately 70% and 50% less As and Cd under AWD than CF irrigation with 500 mg/kg SiO2 NPs addition, suggesting a strong interaction between SiO2 NPs and water irrigation scheme.

Background: In this work, a detector based on optical fiber covered with Multi-Wall Carbon Nanotubes (MWCNTs) was used for sensing and removal of Alizarin from wastewaters. Alizarin is a strong anionic red dye that is part of the anthraquinone dye group. As a rule, this dye is used in the textile industry as a coloring agent. Experiments showed a good efficiency of wastewater treatment. This development could resolve the problem of water contamination with Alizarin red dye. Methods: We used a single-mode fiber SMF-28e with a core diameter of 8.2 μm and a cladding diameter of 125 μm as a base for the tapered optical fiber detector. An MWCNTs array was synthesized on the tapered optical fiber detector surface by spray pyrolysis Chemical Vapor Deposition (CVD) method at 800oC for 20 min inside a tubular furnace, using ferrocene solution in toluene as a catalyst precursor. The formed structure was applied for Alizarin detection in water. Results: According to the patent studies, the nanotubes completely covered the optical fiber surface and the array had a high density with minimal distance between nearby nanotubes. Carbon nanotubes were oriented along the radius of the optical fiber. The average diameter of carbon nanotubes was 24 nm. The optical absorbance levels increased as the Alizarin concentration increased from 50 mg/L to 1000 mg/L. MWCNTs on the optical fiber tapered section adsorbed the dye molecules from aqueous solution. Three intensive absorption bands with the wavelength of the 700, 714 and 730 nm appeared and their intensity increased as the Alizarin concentration increased. The accumulated Alizarin can be recovered by multiple immersing clean water. This property may make tapered optical fiber detector reusable and increase the economic expediency of the sensor application. Conclusions: The study showed higher Alizarin adsorption efficiency of the tapered optical fiber detector compared with relative detectors. This structure can be reusable for dye detection. Removal efficiency for Alizarin reached 98.6%, which makes the tapered optical fiber detector promising for wastewater treatment and dye elimination.

Comprehending the characteristics of nanocatalyst and the effect of pretreatment on its catalytic performance is of great importance in the field of catalysis. The present study probes the catalytic performance of fluorinated Pt/Fe2O3 prepared by one step flame spray pyrolysis and the effect of pretreatment in CO oxidation. The characterization reveals that in‐situ fluorination of Pt/Fe2O3 in high temperature flame process contributed to low temperature reducibility, improved dispersion abundant surface oxygen vacancies and reactive hydroxyl groups. It is noteworthy that the optimal catalytic performance was attained after reduction of fluorinated Pt/Fe2O3 in 10% H2 at 200 °C (F‐Pt/Fe‐200). The abundant surface hydroxyl group and oxygen vacancies facilitated faster reaction. The in‐situ DRIFTS reveals the consumption of hydroxyl group in F‐Pt/Fe‐200 which contributed to the amelioration of CO oxidation. Aside the better stability of F‐Pt/Fe‐200, complete conversion of 2% and 4% CO was achieved at 150 °C and 200 °C, respectively, indicating the feasible utilization of flame‐made fluorinated Pt/Fe2O3. Conclusively, the fluorine formed a strong bond with Pt, which ameliorated oxidative and thermal stability.

Supported gold catalysts have drawn great attention for many decades due to their outstanding performance in remedying the environment from carbon monoxide (CO) pollution. In this study, due to the large surface area of spongy Fe

The effect of ion irradiation on the hardness and yield strength of Zr57Nb5Cu15.4Ni12.6Al10 bulk metallic glass has been studied using nanoindentation and micropillar compression tests. The results for the amorphous alloy were compared with those for 304 stainless steel. After Ni2+ ion irradiation, the metallic glass was found on an average to have 16% lower hardness and 13% lower yield strength. In contrast, 304 stainless steel showed significant hardening (~ 50% hardness and strength increase) after irradiation under identical conditions. The irradiation-induced hardening of the steel was attributed to hindrance of dislocation movement from the defects generated, while the softening behavior of the metallic glass was attributed to structural change in the irradiated region while retaining a fully amorphous state. The present work paves the way for better understanding of the irradiation response of metallic glasses to develop degradation-resistant alloys for next-generation nuclear applications.

A critical parameter in Plasma Electrolytic Oxidation (PEO) is the applied current composed of electronic current caused by sparking and ionic current caused by diffusion of electrolyte ions into the oxide. A wide spectrum of current densities was applied on pure titanium to investigate the PEO mechanism. The growth process and oxide characteristics were investigated by studying the ionic/electronic current contributions during the PEO stages. The contribution of electronic current was found to dominate at low current densities (30 and 40 mA/cm2). The large number of plasma discharges at this condition increases the porosity and coating surface roughness. These discharges provide enough energy to raise the temperature facilitating formation of both stable rutile and metastable anatase. By increasing the current density, the incorporation of ionic current increases resulting in the formation of dense anatase coatings. The highest growth rates achieved at a balance between ionic and electronic charges. HRTEM showed that all coatings are composed of a top amorphous layer produced from electrolyte quenching and an inner layer consisting of a mixture of nanocrystalline and amorphous regions and pores. The interlayer forming at the substrate/coating interface was found to play a key role in the growth mechanism during PEO processing.

High-temperature oxidation resistant amorphous Hf6B10Si31C2N50 and Hf7B10Si32C2N44 films were deposited by reactive pulsed dc magnetron sputtering. To investigate the oxidation mechanism, the films were annealed up to 1500 &deg, C in air. The evolved microstructures were studied by X-ray diffraction and transmission electron microscopy. A three-layered microstructure was developed upon exposure to high temperature. An oxidized layer formed at the top surface for both films consisting of monoclinic and/or orthorhombic m-/o-HfO2 nanoparticles embedded in an amorphous SiOx-based matrix. The as-deposited bottom layer of the films remained amorphous (Hf6B10Si31C2N50) or partially recrystallized (Hf7B10Si32C2N44) exhibiting a h-Si3N4 and HfCxN1&minus, x distribution along with formation of t-HfO2 at its top section. The two layers were separated by a partially oxidized transition layer composed of nanocrystalline h-Si3N4 and tetragonal t-HfO2. The oxidation process initiates at the bottom/transition layer interface with oxidation of Hf-rich domains either in the amorphous structure or in HfCxN1&minus, x nanoparticles resulting in t-HfO2 separated by Si3N4 domains. The second stage occurs at the oxidized/transition layer interface characterized by densely packed HfO2, Si3N4 and quartz SiO2 nanostructures that can act as a barrier for oxygen diffusion. The small t-HfO2 nanoparticles merge and transform into large m-/o-HfO2 while h-Si3N4 forms amorphous SiOx matrix. A similar oxidation mechanism was observed in both films despite the different microstructures developed.

The charge transfer process existing at the metal-support interface of a catalyst is a crucial factor which could be augmented by the creation of vacancy defects. This study reveals the individual and combined effect of Au and Fe promoter in Au-FeOx/ZnO catalysts for CO oxidation. FeOx/ZnO were synthesized with a highly scalable spray pyrolysis method while Au was incorporated by deposition-precipitation strategy. The physicochemical characterization revealed that Fe promoter substituted into the ZnO created abundant oxygen vacancy defects, which favors the interaction of Au on FeOx/ZnO. The anchoring of Au on FeOx/ZnO support substantially enhance charge transfer from Au to support as compared to iron-free Au-ZnO catalyst. However, superfluous Fe load in Au-FeOx/ZnO led to change in structure and deterioration in metal-support interaction. The amelioration in catalytic performance of Au-FeOx/ZnO catalysts was accredited to the strong metal-support interaction and enhanced charge transfer sourcing from the vacancy-mediated Fe promoter in FeOx/ZnO. The optimal catalytic performance was reported on Au-FeOx/ZnO containing 20% which also exhibits good stability while further increment in Fe load reveals adverse effect on the catalytic activity.

We report the high-field superconducting properties of thin, disordered Re films via magneto-transport and tunneling density of states measurements. Films with thicknesses in the range of 9 nm to 3 nm had normal state sheet resistances of $\sim$0.2 k$\Omega$ to $\sim$1 k$\Omega$ and corresponding transition temperatures in the range of 6 K to 3 K. Tunneling spectra were consistent with those of a moderate coupling BCS superconductor. Notwithstanding these unremarkable superconducting properties, the films exhibited an extraordinarily high upper critical field. We estimate their zero-temperature $H_{c2}$ to be more than twice the Pauli limit. Indeed, in 6 nm samples the estimated reduced critical field $H_{c2}/T_c\sim$ 5.6 T/K is among the highest reported for any elemental superconductor. Although the sheet resistances of the films were well below the quantum resistance $R_Q=h/4e^2$, their $H_{c2}$'s approached the theoretical upper limit of a strongly disordered superconductor for which $k_F\ell\sim1$., Comment: 12 pages, 10 figures

The paper deals with Hf–B–Si–C–N films deposited onto Si and SiC substrates using pulsed magnetron co-sputtering of a single B4C–Hf–Si target (at fixed 15% Hf and 20% Si fractions in the target erosion area) in argon–nitrogen gas mixtures. We focus on the effect of the nitrogen fraction in the gas mixture (in the range from 0% to 50%) and of the voltage pulse length (50 μs and 85 μs with the corresponding duty cycle of 50% and 85%, respectively) on the structure and properties of the films. We show that an increasing nitrogen fraction in the gas mixture and consequently in the films (up to 52 at.%) results in a strong amorphization of the film structure, decrease in the film hardness, and rapid rise in the electrical resistivity and the optical transparency of the films. Very high oxidation resistance in air even up to 1500 °C is demonstrated for two sufficiently hard (20–22 GPa) Hf–B–Si–C–N films: the electrically conductive Hf7B23Si22C6N40 film and the optically transparent Hf6B21Si19C4N47 film, both with a contamination level

We report on the microstructure of high-performance thermochromic ZrO2/V0.984W0.016O2/ZrO2 coating deposited on ultrathin flexible glass using a pulsed magnetron sputtering without any substrate bias voltage and post-deposition annealing. The coating combines a low transition temperature of 22 °C, an integral luminous transmittance approaching 50% and a modulation of the solar energy transmittance over 10%. The microstructure of the coating was studied mainly by high-resolution transmission electron microscopy and selected-area electron diffraction. The active V0.984W0.016O2 layer, prepared at a relatively low temperature of 330 °C, is ~70 nm thick. It is composed of closely packed vertically aligned single-crystalline W-doped VO2 nanocolumns that directly attach to the bottom and the top ZrO2 antireflection layer. The majority of the VO2 nanocolumns have a height of ~70 nm (equal to the thickness of the layer) and a lateral size of ~15 nm to 40 nm. The nanocolumns are formed predominantly by the high-temperature thermochromic tetragonal VO2(R) phase with only minor presence of the metastable non-thermochromic orthorhombic VO2(P) phase, which might be stabilized by the used low W-doping. An array of amorphous, low-density nanodomains of a size ~2–4 nm originated particularly along the interface between the V0.984W0.016O2 layer and the top ZrO2 layer. The V0.984W0.016O2 layer is well adhered to both ZrO2 layers. The ZrO2 layers, prepared at a very low temperature (

Tailoring the configuration at metal and support interface contributes to an effective pathway for fabricating catalysts of high catalytic performance for scientific and industrial applications. In this study, the CO oxidation activity over spray-pyrolyzed copper doped Zinc oxide (Cu/ZnO) catalyst was enhanced by deposition–precipitation of 1 wt% Copper (CuxO-Cu/ZnO). Copper ions substituted into ZnO caused defects which altered the physiochemical properties of the catalyst and acted as a bridge to accelerate the transfer of charge carriers to the surface, but the promoting effect of CuxO incorporated by deposition–precipitation elevated the catalytic performance of the catalyst. The activation energy of CuxO-Cu/ZnO (24.52 KJ mol−1) was extremely lower than that of 20 wt% Cu/ZnO (32.19 KJ mol−1) catalyst in CO oxidation due to the active and populous Cu(I) species in CuxO-Cu/ZnO. Defects created by the incorporation of Cu species in CuxO-Cu/ZnO catalyst contributed to low-temperature reducibility, oxygen mobility and abundant oxygen vacancies, which played fundamental role in enhancing the activity of CuxO-Cu/ZnO, compared its counterpart. The critical role of the active Cu+ sites was further confirmed by In-situ DRIFTS.

Reactive high-power impulse magnetron sputtering was used to deposit HfO2 films on Si substrates using a voltage pulse duration, t1, from 100 to 200 μs and an deposition-averaged target power density, , from 7.2 to 54 Wcm− 2. The effects of these processing parameters on the microstructure and properties of the films were studied by atomic force microscopy, nano-indentation, X-ray diffraction, electron diffraction and high-resolution transmission electron microscopy. Four HfO2 films were prepared with (1) t1 = 100 μs, = 7.2 Wcm− 2 (T100S7), (2) t1 = 200 μs, = 7.3 Wcm− 2 (T200S7), (3) t1 = 200 μs, = 18 Wcm− 2 (T200S18) and (4) t1 = 200 μs, = 54 Wcm− 2 (T200S54). All films were found to be composed of an interlayer next to the Si interface followed by a nano-columnar structure layer. The interlayer structure of the films was found to contain a population of lower density nanoscale regions. A reduction in in films T200S54, T200S18, T200S7 and T100S7 caused an increase in the interlayer thickness and a decrease in the width of the nano-columnar structures from ~ 46 nm to ~ 21 nm. This microstructural change was accompanied by a concomitant change of the grain boundary structure from tight and interlocking in films T200S54 and T200S18, to rough and thicker (~ 1 nm) boundaries in films T200S7 and T100S7. Films prepared with larger t1 = 200 μs have a monoclinic HfO2 structure and that with smaller t1 = 100 μs exhibits a mixture of monoclinic and orthorhombic HfO2. A high hardness of 17.0–17.6 GPa was shown for films with a monoclinic HfO2 structure. The films exhibited a refractive index of 2.02–2.11 and an extinction coefficient between 0.1 × 10− 3 and 1 × 10− 3 (both at a wavelength of 550 nm). High refractive index was achieved for films T200S54 and T200S18 owing to the presence of a dense microstructure with sharp and interlocking grain boundaries.

Sustainable applications of nanotechnology in agriculture require insights into the interactions between engineered nanoparticles (ENPs) and clay minerals, a key component in soil that governs the soil properties and functions. This study investigated the charge-dependent interactions of cerium oxide nanoparticles (CeO2NPs) with kaolinite at atomic level with several complementary surface characterization techniques. High resolution transmission electron microscope (HRTEM) and atomic force microscope (AFM) images showed strong attachment of positively charged and neutral CeO2NPs to the surface of kaolinite while the negatively charged CeO2NPs demonstrated low affinity to the surface of kaolinite, indicating strong electrostatic interactions between CeO2NPs and kaolinite surface. Attached CeO2NPs on kaolinite surface displayed charge-dependent aggregation, with neutral CeO2NPs showing the most substantial aggregation on kaolinite surface. The variation in hydrodynamic size and surface charge of kaolinite with the charge on CeO2NPs was observed. The attachment of CeO2NPs also changed the surface charge density distribution on the surface of kaolinite, converting a relatively homogenously charged basal plane into a heterogeneously charged plate. The change on kaolinite surface charge density may markedly affect the interactions of clay minerals with surrounding macro- and micro-nutrients in soil pore water and affect their bioavailability to plants.

Amorfní povlaky Hf–B–Si–C–N vykazují velmi vysokou vysokoteplotní oxidační odolnost. V této práci je zkoumán vývoj mikrostruktury povlaků Hf7B23Si22C6N40 a Hf6B21Si19C4N47 vyžíhaných do 1500 °C s cílem pochopit jejich vysokou oxidační odolnost. Vyžíhané povlaky vykazují dvouvrstvou strukturu zahrnující původní nadeponovaný materiál s horní zoxidovanou vrstvou. Mikrostruktura zoxidované vrstvy je v obou případech tvořena nanokrystalky HfO2 rozptýlenými v amorfní matrici na bázi SiOx. V případě povlaku Hf7B23Si22C6N40 zůstává spodní vrstva amorfní, zatímco v případě povlaku Hf6B21Si19C4N47 částečně rekrystalizuje a tvoří nanokrystalky HfB2 a HfN, které jsou oddělené fázemi h-Si3N4 a h-BN. Fáze HfB2 a HfN vytváří sendvičovou koherentní nanostrukturu spojenou přes monovrstvu (111)-Hf. Navzdory rozdílnému složení původních povlaků vykazuje rozhraní dvouvrstvé struktury v obou případech podobnou mikrostrukturu s jemným rozmístěním nanokrystalků HfO2, které jsou obklopeny fází SiO2. Vysokoteplotní oxidační odolnost obou povlaků je přisuzována konkrétnímu vývoji mikrostruktury obsahující nanokrystalky HfO2 zabudované v husté matrici na bázi amorfního SiOx a krystalického SiO2 (křemen) na rozhraní dvouvrstvé struktury, které slouží jako bariéra pro difúzi kyslíku a přestup tepla. Recently, amorphous Hf–B–Si–C–N coatings found to demonstrate superior high-temperature oxidation resistance. The microstructure evolution of two coatings, Hf7B23Si22C6N40 and Hf6B21Si19C4N47, annealed to 1500 °C in air is investigated to understand their high oxidation resistance. The annealed coatings develop a two-layered structure comprising of the original as-deposited film followed by an oxidized layer. In both films, the oxidized layer possesses the same microstructure with HfO2 nanoparticles dispersed in an amorphous SiOx-based matrix. The bottom layer in the Hf6B21Si19C4N47 coating remains amorphous after annealing while Hf7B23Si22C6N40 recrystallized partially showing a nanocrystalline structure of HfB2 and HfN nanoparticles separated by h-Si3N4 and h-BN boundaries. The HfB2 and HfN nanostructures form a sandwich structure with a HfB2 strip being atomically coherent to HfN skins via (111)-Hf monolayers. In spite of the different bottom layer structure, the oxidized/bottom layer interface of both films was found to exhibit a similar microstructure with a fine distribution of HfO2 nanoparticles surrounded by SiO2 quartz boundaries. The high-temperature oxidation resistance of both films is attributed to the particular evolving microstructure consisting of HfO2 nanoparticles within a dense SiOx-based matrix and quartz SiO2 in front of the oxidized/bottom layer interface acting as a barrier for oxygen and thermal diffusion.

A hard and optically transparent amorphous Hf 7 B 23 Si 17 C 4 N 45 film with a contamination level less than 4 at%, prepared by reactive pulsed dc magnetron sputtering, was subjected to systematic investigation of high-temperature oxidation behavior in air up to 1700 °C. We focus on thermogravimetric analysis of the film in air and on the evolution of the film structure, microstructure and elemental composition with an annealing temperature ranging from 1100 °C to 1700 °C. The film exhibits a superior oxidation resistance up to 1600 °C due to a formation of a nanocomposite protective oxide layer on the surface above 1000 °C. The layer consists of monoclinic and tetragonal (or orthorhombic) HfO 2 nanocrystallites surrounded by a SiO 2 -based amorphous matrix, most probably containing boron. The HfO 2 nanocrystallites exhibit a gradient in size with a dense population of small (a couple of nm) crystallites next to the interface and larger but dispersed crystallites close to the surface.

Pulsed magnetron sputtering in pure Ar was used to deposit multifunctional Hf–B–Si–C films on (0 0 1) silicon substrates using a single B4C–Hf–Si target. The effect of Si content in the microstructure evolution of the films was studied by X-ray photoelectron spectroscopy, X-ray diffraction, electron diffraction and high-resolution transmission electron microscopy. Hf–B–Si–C films with a chemical composition in at% Hf27B57C8, Hf23B55Si2C11, Hf22B54Si9C9 and Hf21B28Si35C7, respectively were produced using a fraction of 0%, 1%, 7.5% and 30% Si in the target erosion area. The Hf27B57C8 film is composed of hexagonal HfB2 nano-columnar structures (∼50–60 nm long, and ∼5–10 nm wide). The nano-columnar structures exhibit a preferred orientation with the (0 0 1) tilted ∼30° away from the film surface. The Hf23B55Si2C11 film consists of finer HfB2 nanocrystal columnar structures (∼20–30 nm long and

The performances of supported noble metal catalysts are closely related to the size, composition, structure and metal-support interaction. In the current work, bimetallic Pt-Au nanoalloys are loaded in situ on titanium dioxide in one step by flame spray pyrolysis (FSP). The formation of alloyed Pt-Au nanocrystals without phase separation is systematic proven by various characterization methods. And in-situ DRIFTs and XPS reveal the electronic synergy effect between Au and Pt weakens the agglomeration of the noble metal and reduces the CO poisoning. This synergy effect makes the alloy catalyst's low-temperature catalytic activity increase by 20% compared to the single-metal Pt catalyst. The total conversion temperature (T100) increase by 100 °C relative to the Au catalyst. As a continuous and scalable industrial production process, FSP can produce alloys and other new structural materials with less time and cost, compared to other wet preparation methods.

BaCO3 and BaTiO3 layers were coated on titanium by plasma electrolytic oxidation at 5 mA/cm2 in 0.5 M Ba(CH3COO)2 and 2 M NaOH electrolyte. Coatings were investigated by scanning electron microscopy, X-ray and electron diffraction, and high-resolution transmission electron microscopy (HRTEM). Processing for 1 h required low voltages producing a BaCO3 coating along with a thin TiO2 interlayer (~60 nm). The coating is composed of orthorhombic BaCO3 nanorods that were vertically oriented at the bottom layer close to Ti substrate and horizontally oriented in the top layer close to the surface. Processing for 4 h required higher voltages resulting in generation of microarc discharges and discharge channel formation. These conditions produced a tetragonal BaTiO3 coating along with a broader TiO2 interlayer at the Ti interface composed of rutile and brookite nanostructures. It is suggested that the discharge channels promote the oxidation of the substrate along with the migration of titanium ions to the coating facilitating the BaCO3 to BaTiO3 transformation. The HRTEM evidence suggests that the latter transformation occurs via an epitaxial relationship existing between the BaTiO3 and BaCO3 crystal structures. Based on the present evidence, a structural model is proposed to describe the BaTiO3 growth from the BaCO3 lattice.

In this work, we present a facile technique based on electrophoretic deposition (EPD) to produce transition metal hydroxide decorated carbon nanotubes (CNT) for electrochemical applications. We specifically explore the performance of nickel-cobalt hydroxides given their high activity, conductivity and stability as compared to the individual hydroxides. We exploit the high local pH at the negative electrodes during water-based EPD to form nanoparticles of nickel-cobalt hydroxides in situ on the CNT surface. We focus our work here on obtaining functional and conductive deposits on CNTs. The hydrophilic binderless deposits of Ni-Co double hydroxide decorated CNTs obtained here are used for non-enzymatic glucose detection. XPS data and electrochemical testing reveal difference in the deposited double hydroxide based on chronology of charging salt addition even at the same ratio. When cobalt and nickel salts are sequentially added at a ratio of 1:1, the deposited double hydroxides show excellent glucose sensitivity of ~3300μA/mM.cm2 at applied potential of 0.55V vs. Ag/AgCl reference electrode.

The treatment of MWCNTs with the water-soluble cobalt octacarboxyphthalocyanine derivative theraphthal under ultrasonic conditions led to the dispersion and unfolding of MWCNTs, producing onion-like carbon nanostructures and graphene sheets. This differs from the conventional concepts of classic π–π stacking interactions and/or σ-bonding between macrocycles and carbon nanotubes, as well as differing from the classic high-temperature formation of carbon nano-onions.

Highly oriented multilayerd Ba(Zr0.1Ti0.9)O3/(Ba0.75Ca0.25)TiO3 thin films were fabricated on Nb doped (001) SrTiO3 (Nb:STO) substrates by pulsed laser deposition. Microstructural characterization by X-ray diffraction indicates that the as-deposited multilayered thin films are highly c-axis oriented. Transmission electron microscopy shows that the films present epitaxial correspondence with the substrate at the first layer and multi-oriented twin domain structures near the surface, especially with increasing periodic number (N). Piezoresponse force microscopy (PFM) studies reveal an intense polarization component in the out-of-plane direction, which increases greatly with increasing periodic number (N), whereas the in-plane shows inferior phase contrast. The optimized combination was found to be the annealed 16 layer structure (N = 8, layer thickness = 712 nm) which displays the best polarization domain structures and the saturated piezo response loop. The annealing process benefits the 180° domains with the same angle in the growth direction, which brings more piezo response in the in-plane signal. Our results suggest that the increasing of piezo response is greatly associated with the interface effect and the twining structure.

The electromagnetic shielding effectiveness of C–SiC/epoxy composites was investigated and compared with that of carbon fiber/epoxy composites. C–SiCs, short fibers with carbon cores and silicon carbide shells, were fabricated by a carbothermal reduction process using chopped carbon fibers (CFs) and rice husk ash. After presenting the morphology and structure of the C–SiC fibers, the electromagnetic interference shielding effect of SiC coated carbon short fibers is discussed. The Kα-band (26.5–40.0 GHz) shielding studies revealed that the maximum total shielding effectiveness (SET) of the composite with 25 vol% of C–SiCs is 17.07 dB, dominated by absorption, while the composite with 25 vol% of the same sized carbon fibers has a SET of 8.44 dB only.

The microstructures of two layered films consisting of 2% Mn doped (Ba,Sr)TiO3 (Mn:BST) and 2% Mn doped Ba (Zr, Ti)O3 (Mn:BZT) layers on a MgO (001) substrate deposited by pulsed laser deposition were studied using X-ray diffraction (XRD), atomic force microscopy (AFM), transmission electron microscopy (TEM), high-resolution TEM and nanoindentation. The films contained four alternating layers of Mn:BST and Mn:BZT either the former or the latter as the first layer. The film deposited with Mn:BST as the first layer has a rough surface, an epitaxial continuous layer structure for the first two layers next to the interface and columnar structures for the top two layers. The first layer has a single oriented crystal structure with an in-plane lattice mismatch of ∼−5.70% and an atomically sharp interface with respect to the substrate. The second layer exhibited twin-induced domain structures. The columnar structures in the top two layers have an average width of ∼70 nm and are tightly attached to their adjacent...

Since the development of the posterior lumbar interbody fusion (PLIF) and anterior approach for anterior cervical discectomy and fusion (ACDF) many different fusion substrates such as grafts and devices, have been explored. This includes autografts, allografts, and interbody spacers made from polyether-ether-ketone (PEEK), porous tantalum and titanium.In an attempt to combine only the advantages from both the PEEK and titanium interbody devices, a novel type of PEEK titanium composite (PTC) interbody fusion device has been developed. This device combines a PEEK core with titanium alloy endplates made from a novel 3-dimensional (3D) titanium mesh (Ti6Al4V) to potentially enable a better bone apposition and ingrowth while enabling imaging of the fusion site.This chapter covers how the novel PTC interbody devices are manufactured, which applications the PTC technology have currently been applied to, and how the mechanical properties of the interbody devices that employ the PTC technology compare to that of standard PEEK devices. In addition, the surface topography of the Ti6Al4V endplates will be discussed alongside a presentation of several in vitro and in vivo studies that have been completed for the PTC technology. Specifically, two in vitro studies will be presented showing the effect of each of the structural components (PEEK, Ti6Al4V) on the proliferation and differentiation of immature and mature osteoblasts. Furthermore, two in vivo studies will illustrate the effect of the structural components (PEEK, Ti6Al4V) on bone ingrowth/ongrowth and biocompatibility in a rabbit model, and the effect of a clinical PTC device in an ovine lumbar fusion model. Lastly, a discussion will summarize the presented studies and make the case for the PTC technology as a new standard for interbody devices in spine fusion.

Hf-B-Si-C films were deposited onto silicon and glass substrates using pulsed magnetron co-sputtering of a single B4C-Hf-Si target (at a fixed 15% Hf fraction and a varying 0–50% Si fraction in the target erosion area) in pure argon. We focus on the effect of the Si content in the films. The film structure changes from nanocolumnar (at 0–7 at.% of Si) to nanocomposite (at around 10 at.% of Si) to amorphous (at higher Si contents). Both nanocolumnar and nanocomposite HfB2-based films exhibit a hardness of up to 37 GPa and a high H/E* ratio of around 0.15. The Si incorporation leads to a significant reduction of the compressive stress of films and improvement of their oxidation resistance (unmeasurable mass change after annealing up to 800 °C at 35 at.% of Si). All films exhibit a high electrical conductivity and very smooth defect-free surfaces with an average roughness below 1 nm. Consequently, the films may be used as a new class of hard and electrically conductive protective coatings with a high oxidation resistance at elevated temperatures.

Pulsed reactive magnetron sputtering was used to deposit Zr–B–C–N films as a function of the N 2 /Ar ratio in the plasma. The microstructure evolution of the films was studied by high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy and nanoindentation. Zr–B–C–N films with a chemical composition (in at.% without 1–2 at.% H and 61 B 27 C 6 N 3 , Zr 41 B 30 C 8 N 20 , Zr 26 B 26 C 5 N 42 and Zr 24 B 19 C 6 N 49 were produced using a nitrogen fraction of 0%, 5%, 10% and 15%. The Zr 61 B 27 C 6 N 3 film consists of fcc B-rich Zr(B,C,N) nano-columnar structures concealed by an amorphous matrix. The fcc B-rich Zr(B,C,N) columns exhibit a preferred orientation with their [1 1 1] parallel to the film growth direction. The Zr 41 B 30 C 8 N 20 film possesses the highest hardness and consists of nano-needle structures (∼40 nm long and ∼10 nm wide) separated by amorphous boundaries. The nano-needles have a face-centered cubic (fcc) structure and are composed of ZrN and/or Zr(B,C,N) nano-domain structures (∼2 nm) that are semi-coherently joined via Zr–N monolayer interfaces. The Zr 26 B 26 C 5 N 42 film is composed mainly of refined crystalline ZrN nano-needle structures (∼2 nm) embedded in an amorphous structure, and the Zr 24 B 19 C 6 N 49 film has an amorphous-like structure. In the Zr 41 B 30 C 8 N 20 film, the formation of ZrN and/or Zr(B,C,N) nano-domain structures, semi-coherently joined via Zr–N monolayer interfaces within the nano-needle structures, play a critical role in achieving high hardness and modulus. The annihilation of such a structure and the introduction of additional amorphous structure into the films by changing the N/Zr ratio via varying the N 2 fraction in the gas mixture result in a significant decrease in the mechanical properties.

Barium titanate thin films deposited on MgO (0 0 1) by RF magnetron sputtering are composed of two new superstructures Ba4Ti5O10 and Ba4Ti4O11 formed as epitaxial nanodomain structures. Due to the nanometre scale size of domains and the complexity of the structure in the film, the single-crystal X-ray diffraction technique does not have the capability for the crystallographic structure determination of the two new superstructures. We used nanobeam electron diffraction to reconstruct the three-dimensional diffraction space and hence the symmetry of the new superstructures. Both Ba4Ti5O10 and Ba4Ti4O11 are monoclinic structures with a space group of Cm (b-unique axis). Ba4Ti5O10 has a lattice parameter a = 16.49 A, b = 3.94 A, c = 8.94 A and β = 103°, while Ba4Ti4O11 has a = 17.88 A, b = 3.94 A, c = 7.21 A and β = 98°. Atomic structural models for the two new superstructures were established by reconstructing the high-resolution transmission electron microscopy (HRTEM) images taken from the three major axes...

Single-crystalline perovskite LaBaCo2O5.5+δ thin films were grown on a (110) NdGaO3 single-crystal substrate in order to systematically investigate the effect of lattice mismatch on the electrical transport properties in comparison to the films on LaAlO3, SrTiO3, and MgO substrates. Microstructure studies reveal that all of the LaBaCo2O5.5+δ films are of excellent quality with atomically sharp interface structures. The electrical and magnetic transport property studies indicate that the resistivity, magnetoresistance, and magnetic moment of the film are very sensitive to the substrate materials because of the lattice mismatch/interface strain. The Curie temperature, however, is almost independent of the strain imposed by the substrate, probably because of the strong coupling between the nanodomain boundary and interface strain.

Environment-friendly Ferroelectric Mn:BST//Mn:BZT multilayer with additional 2% Mn doping were epitaxially fabricated on (001) MgO substrates by pulsed laser deposition with same thickness but different stacking periodic numbers or each layer thickness. Microstructure studies by X-ray diffraction and transmission electron microscopy indicate that the multilayer is c-axis oriented with good epitaxial nature. The microwave (∼18GHz) dielectric property measurements show that the dielectric loss tangent rapidly decreases with the increase of each layer thickness. The loss tangent can be lowered down to ∼0.043 at ∼18GHz, which suggests that the Mn:BST//Mn:BZT multilayer system has great potential for the development of room temperature microwave elements and related applications.

Highly directional-dependent metal-insulator transition is observed in epitaxial double perovskite LaBaCo2O5.5+δ films. The film exhibit metallic along [100], but remain semiconducting along [010] under application of a magnetic field parallel to the surface of the film. The physical origin for the properties is identified as in-plane tensile strain arising from oxygen vacancies. First-principle calculations suggested the tensile strain drastically alters the band gap, and the vanishing gap opens up [100] conduction channels for Fermi-surface electrons. Our observation of strain-induced highly directional-dependent metal-insulator transition may open up new dimension for multifunctional devices.

In this work, we have employed high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) and nano indentation to study the microstructure and the mechanical properties of Si-B-C-N films treated at high temperatures. Si-B-C-N films with a chemical composition of Si30–32B10–12C2–4N49–51 were deposited in a 50% Ar/50% N2 gas mixture by pulsed DC magnetron sputtering. In order to study the microstructure at elevated temperatures of the films, they were subjected to annealing at temperatures up to (i) 1400 °C in He and (ii) 1700 °C in air. XPS studies showed that annealing to 1400 °C in He does not affect the chemical composition of the film, while annealing to 1700 °C in air results in the oxidation of the film via the loss of N and B and formation of SiOx. HRTEM studies demonstrated that the as-deposited film and the film annealed to 1400 °C in He are amorphous. A three-layer structure was found in the film annealed to 1700 °C in air: the original amorphous Si-B-C-N base-layer, a transition nanocomposite layer consisting of BN nanocrystals embedded in a SiOx amorphous matrix and an amorphous SiOx top layer. The present evidence suggests that O reacts with Si in the Si-B-C-N amorphous structure resulting in the formation of SiOx and concomitant nucleation of BN crystals at the base/transition layer interface. Nano-indentation tests show that the film annealed to 1400 °C in He has a hardness of 22.1 GPa and a modulus of 210.8 GPa, higher than that of the as-deposited film (19.5 and 204.9 GPa), whereas the values for the film annealed to 1700 °C in air (9.8 and 76.5 GPa) simply reflect those of the SiOx top layer. The high oxidation resistance of the films is attributed to the presence of BN in front of the base layer interface that can act as a barrier to O diffusion.

Highly directional-dependent metal-insulator transition is observed in epitaxial double perovskite LaBaCo2O5.5+δ films. The film exhibit metallic along [100], but remain semiconducting along [010] under application of a magnetic field parallel to the surface of the film. The physical origin for the properties is identified as in-plane tensile strain arising from oxygen vacancies. First-principle calculations suggested the tensile strain drastically alters the band gap, and the vanishing gap opens up [100] conduction channels for Fermi-surface electrons. Our observation of strain-induced highly directional-dependent metal-insulator transition may open up new dimension for multifunctional devices.

Interface engineered BaTiO3/SrTiO3 heterostructures were epitaxially grown on (001) MgO substrates by pulsed laser deposition. Microstructural characterizations by X-ray diffraction and transmission electron microscopy indicate that the as-grown heterostructures are c-axis oriented with sharp interfaces. The interface relationships between the substrate and multilayered structures were determined to be [001]SrTiO3//[001]BaTiO3//[001]MgO and (100)SrTiO3//(100)BaTiO3//(100)MgO. The high-frequency microwave (∼18 GHz) dielectric measurements reveal that the dielectric constant and dielectric loss of the nanolayered heterostructures are highly dependent upon the stacking period numbers and layer thicknesses. With the increase in the periodic number, or the decrease in each layer thickness, the dielectric constant dramatically increases and the dielectric loss tangent rapidly decreases. The strong interface effect were found when the combination period is larger than 16, or each STO layer is less than 6.0 nm. T...

Ferromagnetic thin films of the A-site nano-ordered double perovskite LaBaCo(2)O(5.5+δ) (LBCO) were grown on (001) MgO, and their structural and magnetic properties were characterized. The as-grown films have an excellent epitaxial behavior with atomically sharp interfaces, with the c-axis of the LBCO structure lying in the film plane and the interface relationship given by (100)(LBCO)//(001)(MgO) and [001](LBCO)//[100](MgO) or [010](MgO). The as-grown LBCO films exhibit a giant magnetoresistance (54% at 40 K under 7 T) and an anomalous magnetic hysteresis, depending strongly on the temperature and the applied magnetic field scan width.

The predicted energy demand will reach 28 TW by 2050 and 46 TW by 2100. The deployment of solar cells as a source of electricity will have to expand to a scale of tens of peak terawatts in order to become a noticeable source of energy in the future. Of the current commercial and developmental solar cell technologies, the majority have natural resource limitations that prevent them from reaching a terawatt scale. These limitations include high energy input for crystalline-Si cells, limited material production for GaAs cells, and material scarcity for CdTe, CIGS, dye-sensitized, crystalline-Si, and thin-film Si cells. In this paper, we examine these limitations under the best scenarios for CdTe, CIGS, GaAs, dye-sensitized, and crystalline-Si solar cells. Without significant technological breakthroughs, these technologies combined would meet only a few percentage points (∼2%) of our energy demand in 2100.

Environment friendly ferroelectric relaxor Ba ( Zr 0.2 Ti 0.8) O 3 thin films with the addition of 2% Mn dopant were grown on (001) MgO substrates by pulsed laser deposition. Microstructure studies with X-ray diffraction and transmission electron microscopy reveal that the as-grown Ba ( Zr 0.2 Ti 0.8) O 3 thin films are c-axis oriented with an atomic sharp interface. The films have good single crystallinity and good epitaxial quality. The interface relationship was determined to be [100]Mn:BZT//[100]MgO and (001)Mn:BZT//(001)MgO . Nanoscale order/disorder relaxor structures were found with nano-columnar structures. The microwave dielectric measurements (15–18 GHz) indicate that the films have excellent dielectric properties with large dielectric constant value, high tunability, and low dielectric loss, promising the development of room temperature tunable microwave elements.

We report a facile synthesis and characterization of highly-dispersed platinum nanoparticles supported on Ketjen carbon black (Pt/C) as electrocatalysts for polymer electrolyte membrane fuel fells (PEMFCs). Pt particles with size of ∼ 2.6 nm were synthesized through adsorption of Pt acetylacetonate on carbon supports and subsequently thermal decomposition. A comparative characterization analysis, including X-ray diffraction (XRD), high resolution transmission electron microscope (HR-TEM), cyclic voltammetry (CV), and hydrodynamic voltammetry measurements, was performed on the synthesized and commercial TKK catalysts. It revealed the details of Pt dispersion on the carbon support, particle size and distribution, electrochemical surface area (ECSA), and oxygen reduction reaction (ORR) activity of the catalysts. It was found that the synthesized Pt/C has similar particle size to that of the TKK catalyst (2.6 nm and 2.7 nm, respectively), but narrower particle size distribution. Accelerated durability tests under potential cycles were performed to study electrochemical degradation of the catalysts in corrosive environments. The synthesized Pt/C displayed significant losses in ECSA and activities after 20 k potential cycles, especially from 5 k to 20 k cycles, though with higher initial values (43% and 79% higher in ECSA and mass activity, respectively).

Synthesis of high quality epitaxial LaMnO3 and (La,Sr)MnO3 films on large areas is highly desirable. Recently, we have deposited LaMnO3 and (La,Sr)MnO3 films on the MgO (001) and LaAlO3 (001) substrates using RF magnetron sputtering. Highly epitaxial quality thin films have been successfully obtained at 750 °C by manipulating processing parameters as characterized by X-ray diffraction, electron diffraction and HRTEM. The epitaxial LaMnO3 and (La,Sr)MnO3 thin films have either a tetragonal or orthorhombic crystal structure depending on the film (target) composition and substrate type. The (La,Sr)MnO3 films were found to have an orthorhombic crystal structure when deposited on LaAlO3 substrate and a tetragonal structure when deposited on MgO substrate; whereas LaMnO3 films have a tetragonal structure when deposited on LaAlO3 substrate and an orthorhombic crystal structure when deposited on MgO substrate. The orthorhombic structures of the (La,Sr)MnO3 film on LaAlO3 and LaMnO3 on MgO are oriented with their c-axis on the film plane. Magnetic studies show that the epitaxial films have higher phase transition temperature than the corresponding bulk material and to those obtained using pulse laser deposition. Successful synthesis of highly epitaxial quality films by RF magnetron sputtering over a larger area can result in reduced cost for fabricating and processing epitaxial thin films.

The predicted energy demands will reach 28 terawatts by 2050 and 46 terawatts by 2100. The deployment of solar cells as a source of energy will have to expand to a scale of tens of peak terawatts in order to become a noticeable source of energy in the future. Of the current commercial and developmental solar cell technologies, the majority have natural resource limitations that prevent them from reaching a terawatt scale. These limitations include high energy input for crystalline-Si cells, limited material production for GaAs cells, and material scarcity for CdTe, CIGS, dye-sensitized, crystalline-Si, and amorphous Si cells. In this paper, we examine these resource limitations under the best scenarios, i.e. the maximum possible power from each of these solar cell technologies. Without significant technological breakthroughs, these technologies combined would meet only 1 - 2% of our energy demands in 2100.