The electrochemical performance of an anode material for a solid oxide fuel cell (SOFC) depends highly on microstructure in addition to composition. In this study, a NiO–yttria‐stabilised zirconia ...(NiO–YSZ) composite with a highly dispersed microstructure and large pore volume/surface area has been synthesised by ultrasonic spray pyrolysis (USP) and its electrochemical characteristics has been investigated. For comparison, the electrochemical performance of a conventional NiO–YSZ is also evaluated. The power density of the zirconia electrolyte‐supported SOFC with the synthesised anode is ∼392 mW cm–2 at 900 °C and that of the SOFC with the conventional NiO–YSZ anode is ∼315 mW cm–2. The improvement is ∼24%. This result demonstrates that the synthesised NiO–YSZ is a potential alternative anode material for SOFCs fabricated with a zirconia solid electrolyte.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
The effects of N-doping, and N-In co-doping on ZnO films were studied by analyzing the structural, electrical, and optical properties of the films prepared by using an ultrasonic spray pyrolysis ...(USP) method. According to scanning electron microscopy (SEM) data, all films had very complex surface structures. Their polycrystallinity were also proven by using an X-ray diffraction method. The Hall-effect measurement showed that both the undoped and the N-doped ZnO films exhibited n-type conductivity and that the N-In co-doped ZnO film showed p-type conductivity. In the extended X-ray absorption fine structure (EXAFS) analysis, the number of oxygen atoms in the N-In codoped ZnO films was found to be larger than that in the N-doped and the undoped ZnO films. The photoluminescence spectra also showed that the N-In co-doping suppressed the concentration of oxygen vacancies in the ZnO films. Through an effective incorporation of indium atoms, more oxygen atoms seem to have been introduced into the lattice of the N-In co-doped ZnO films.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Nanotechnology belongs to the key innovative technologies for powder production. Ultrasonic spray pyrolysis is a versatile method for the formation of nanosized particles of metals, oxides and ...composites. This work deals with Ag, Cu and Au nanoparticles formed by ultrasonic spray pyrolysis using the horizontal and vertical reactor. Furthermore, a direct synthesis of Ru-TiO2 and RuO2-TiO2 nanoparticles with the core and shell structure was investigated. The molar fractions of precursors, solvent type, and the process temperature play the crucial role in the formation of core and shell structures. Moreover, the influence of the reaction parameters (temperature, residence time, solution concentration and ultrasonic frequency) on the morphological characteristics of the prepared nanoparticles was studied. A decrease in the solution concentration decreases the final nanoparticle size. An increase in temperature from 150°C to 1000°C leads from an irregular form to a more spherical one. Subsequently, a model of metallic nanoparticle formation from an aerosol droplet could be proposed. Using ultrasonic spray pyrolysis, ideal spherical metallic particles were obtained at temperatures above the melting point. A scanning mobility particle sizer (SMPS) was used for the on-line determination of nanoparticle size distribution. The collection of nanosized particles was performed in an electrostatic field. The scale up of the ultrasonic spray pyrolysis method was successfully applied for the synthesis of silver powder from a water solution of silver nitrate. / Нанотехнология является ключевой иновационной технологией в производстве порошковых изделий. Распыление порошков ультразвуковым пиролизом имеет широкое применение в сфере образования частиц нанопорошковых металлов, оксидов и композитов. Данная работа освещает процессы образования наночастиц серебра, меди и золота методoм ультразвукового пиролиза, с использованием горизонтального и вертикального реакторов. Исследуется прямой синтез наночастиц на основе Ru-TiO2 и RuO2-TiO2 со структурой ядро-оболочка. Молярный состав прекурсора, вид растворителя и средняя температура играют важную роль в образовании частиц, имеющих такую структуру. В работе представлен анализ воздействия реакционных свойств (температура, время задерживания, концентрация раствора и частота ультразвука) на морфологические характеристики наночастиц. Повышение температуры от 150°C до 1000°C может вызвать, как деформирование частицы, так и образование сферической частицы. В работе также рассматривается новая модель образования металлических наночастиц из капли аэрозоля. В процессе распыления ультразвуковым пиролизом идеальные сферические частицы образуются при температуре ниже точки плавления. Для сортировки величины частиц на основании траектории движения частиц в электростатическом поле используется устройство, данные которого отслеживаются в режиме онлайн. Сбор наночастиц проводится в электростатическом поле. Рост производственных объемов порошковых изделий, изготовленных методом ультразвукового распылительного пиролиза способствовал успешному внедрению данного метода для синтеза порошка серебра из раствора серебра нитрата. / Nanotehnologija pripada ključnim inovativnim tehnologijama za proizvodnju prahova. Raspršivanje prahova ultrazvučnom pirolizom višestruko je korišćeno za formiranje čestica nanoprahova metala, oksida i kompozita. Ovaj rad odnosi se na nanočestice srebra, bakra i zlata, formiranih ultrazvučnom pirolizom korišćenjem horizontalnog i vertikalnog reaktora. Direktna sinteza nanočestica na bazi Ru-TiO2 i RuO2-TiO2 sa strukturom sastavljenom od jezgra i ljuske dalje je ispitivana. Molarni udeli prekursora, tip rastvarača i procesna temperatura imaju odlučujuću ulogu u formiranju čestica sa ovom kombinovanom strukturom. Zatim, ispitivan je uticaj reakcionih parametara (temperatura, vreme zadržavanja, koncentracija rastvora i frekvencija ultrazvuka) na morfološke karakteristike pripremanih nanočestica. Uvećanje temperature od 150°C do 1000°C vodi od jednog nepravilnog oblika do proizvodnje sfernih čestica. Nakon toga, bio je predložen model formiranja metalnih nanočestica od kapi aerosola. Korišćenjem procesa raspršivanja preko ultrazvučne pirolize idealno sferne čestice dobijene su na temperaturi ispod tačke topljenja. Uređaj za određivanje raspodele veličine čestica korišćenjem različite pokretljivosti čestica u elektrostatičkom polju korišćen je za on-line analizu tokom proizvodnje čestica. Sakupljanje nanočestica izvršeno je u elektrostatičkom polju. Uvećanje proizvodnje prahova raspršivanjem ultrazvučnom pirolizom uspešno je primenjeno za sintezu prahova srebra iz vodenog rastvora srebronitrata. /
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IZUM, KILJ, NUK, ODKLJ, PILJ, PNG, SAZU, UL, UM, UPUK
In this paper, we report the synthesis of two-dimensional wall like carbon nanostructures (i.e. carbon nanowalls) by ultrasonic spray pyrolysis of ethanol and fullerene mixture. At higher temperature ...carbon nanofibers were formed on the substrate placed at the center of the reactor tube, whereas carbon nanowalls were observed on the substrate placed downstream of the tube below 100
°C. Spaces between the nanowalls changed with distance of the substrates from the furnace. Qualitative analysis of materials was performed using scanning electron microscopy, transmission electron microscopy and Raman spectroscopy.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Low-temperature method for the synthesis of novel morphology of needle-like nanoparticles of disodium dimolybdate (Na2Mo2O7) in the process of ultrasonic spray pyrolysis (USP) using aqueous solutions ...of thermodynamically stable molybdenum (VI) oxide clusters as precursor is described. Needle-like Na2Mo2O7 particles were obtained and collected in toluene, while centrifugation was employed to isolate solid material from solution. The scanning electron microscopy (SEM) confirmed that the morphology of the synthesized Na2Mo2O7 particles is needle-like collected into bundles. The X-ray Powder Diffraction (XRPD) analysis revealed appearance of orthorhombic Na2Mo2O7, synthesized at 300 °C. By comparing the XRPD pattern of the synthesized needle-like Na2Mo2O7 powder obtained in the process of USP with the XRPD pattern simulated for randomly-distributed crystallites by planes, the most prefered growth plane of needle-like nanoparticles were found.
Nitrogen-doped ZnO films were deposited on silicon (1
0
0) substrate using zinc acetate and ammonium acetate aqueous solution as precursors by ultrasonic spray pyrolysis. Successful p-type doping can ...be realized at optimized substrate temperature. The p-type ZnO films show excellent electrical properties such as hole concentration of ∼10
18
cm
−3, hole mobility of ∼10
2
cm
2
V
−1
s
−1 and resistivity of ∼10
−2
Ω
cm. In the photoluminescence measurement, a strong near-band-edge emission was observed, while the deep-level emission was almost undetectable in both undoped and N-doped ZnO films. The growth and doping mechanism of N-doped ZnO films were discussed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The morphology of TiO2 nanoparticles deposited on a QCM sensor is crucial in its mechanical loading. Different heating treatments transform the morphology of TiO2 nanoparticles, affecting the loading ...and hence shifting the resonant frequency and changing the impedance QCM value. In this research, the deposition of TiO2 nanoparticles was carried out above QCM using the ultrasonic spray pyrolysis (USP) technique with variations in calcination temperature of 200, 230, and 250 °C. The analysis results show that the increase in the agglomeration and particle size causes an increase in the inertial mass of TiO2 nanoparticles.
HIGHLIGHTS
The size of TiO2 agglomerates and their particles increases as the calcination temperature is raised
Higher calcination temperature resulted in a larger frequency shift of the QCM oscillation due to the layer inertial mass increase
Larger TiO2 nanoparticle size significantly increases the layer’s resistance, contributing to higher impedance
GRAPHICAL ABSTRACT
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
In this study, the structure and substructure of SiO
2–Mg phosphate tungsten bronzes, MgPTB, (MgHPW
12O
40
·
29H
2O) obtained by ultrasonic spray pyrolysis method from a silica sol, and a MgPTB ...solution, obtained by the ion exchange method, as precursors were investigated.
The mechanism of the formation of aerosol droplets is discussed. Phase composition, structure and substructure of SiO
2–MgPTB particles were investigated by X-ray powder diffraction (XRPD) analysis, transmission electron microscopy (TEM), and scanning electron microscopy (SEM).
Good agreement between the theoretically predicted values for the mean diameters of particles and subparticles (1.27
μm and 75.4
nm, respectively) and the experimentally obtained ones (1.17
μm and 65–90
nm) was found.
This agreement confirms the applicability of the model to get a satisfactory prediction of the most important data related to the nano-structural design of SiO
2–MgPTB powders.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Issue Title: Special Issue: ICE-2005 International Conference on Electroceramics The ceramic interconnect,La^sub 0.8^Sr^sub 0.05^Ca^sub 0.15^(Cr^sub 1 -x^, B^sub x^)O^sub 3^ (B = Cu, Ni, V, x = 0.02, ...0.1, 0.5) (LSCCB) powders were prepared by Pechini method, Ultrasonic Spray Pyrolysis (USP) and Glycine Nitrate Process (GNP). Nano sized powders were synthesized by GNP and their chemical compositions were confirmed by ICP analysis. The electrical conductivities of LSCCCu, LSCCNi, and LSCCV samples were 34 S/cm, 48 S/cm, and 22 S/cm at 800^sup ^C in air, respectively. Among the LSCCB powders, the LSCCNi sample shows highest relative density and electrical conductivity. In a low oxygen partial pressure, however, LSCCV sample was more stable. The perovskite phase of the composition LSCCV sample is of large practical interest for interconnects in SOFC because of the stability in low oxygen partial pressure.PUBLICATION ABSTRACT
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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