scholarly journals Fast and simultaneous doping of Sr0.9−−−Ca0.1In2O4:(xEu3+, yTm3+, zTb3+) superstructure by ultrasonic spray pyrolysis

2019 ◽  
Vol 56 ◽  
pp. 14-24 ◽  
Author(s):  
A.A.G. Santiago ◽  
L.X. Lovisa ◽  
P.N. Medeiros ◽  
M.S. Li ◽  
N.L.V. Carreño ◽  
...  
2018 ◽  
Vol 15 (2) ◽  
pp. 147-156
Author(s):  
Rebeka Rudolf ◽  
Urban Ferčec ◽  
Mohammed Shariq

Background: This review provides a closer look at recent work in the field of fireworks manufacture, which could see the replacement of micron-sized particles with their nano-scaled counterparts. Moreover, we also discuss micron-sized particles as well as nanoparticles (NPs) from K, Fe, Al, Ti, Ba, etc., that are produced in the atmosphere as a result of these fireworks. One of the possible technological substitutes for fireworks is presented in detail, i.e., the use of ultrasonic spray pyrolysis (USP) technology. Method: We searched Google, Web of Science and PubMed for a literature survey of fireworks and their products: firecrackers, micron-sized and nanoparticles. Moreover, we used some of our own knowledge and experimental data to strengthen the possibility of simulating the synthesis of firework products on the laboratory scale. Results: The use of nano reactants and oxidisers has seen a substantial increase in the sound efficiency and a decrease in the amount of chemicals used, making fireworks more eco-friendly. The application of Al- and Ti-based nano flash powder in the size range from 35 nm to 50 μm resulted in a significant improvement in the ignition properties of the fireworks. Under changing aerodynamic conditions, it is difficult to collect them as samples for real-time monitoring, needed for their characterization or the testing of their harmfulness under laboratory conditions. As a result, NPs below 100 nm in the surroundings could be easily inhaled into the lungs and cause more pulmonary and respiratory problems than micron-sized particles. USP produces nanoparticles in the laboratory that could replace the conventional micron-sized firecracker raw materials, or nanoparticles that are similar to those formed by fireworks. It will also help to identify the physiochemical properties of the airborne particulates in order to understand and evaluate their impact. </P><P> This review could be valuable for a controlled economic synthesis through USP, and in the use of nanopowders in pyrotechnology that could reduce pollution to a great extent, thus contributing to the growth and good practise of the fireworks industry. With respect to the USP synthesis, we have also discussed in detail the physical (size, shape) and chemical (composition) characteristics of Al2O3 and TiO2 NPs from different precursors and their temperature ranges. An in-depth explanation for a comparative analysis for the formation mechanism of nanoparticles through both fireworks and USP is presented in the final section. We can produce nanoparticles in the laboratory with ultrasonic spray pyrolysis that have similar properties to those produced from fireworks and can then be used for further testing.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Inti Zumeta-Dubé ◽  
José Manuel García Rangel ◽  
Jorge Roque ◽  
Issis Claudette Romero-Ibarra ◽  
Mario Fidel García Sánchez

AbstractThe strong facet-dependent performance of glass-supported CeO2 thin films in different applications (catalysis, smart windows, etc.) has been the target of diverse fundamental and technological approaches. However, the design of accurate, cost-effective and scalable methods with the potential for large-area coverage that produce highly textured glass-supported CeO2 thin films remains a technological challenge. In the present work, it is demonstrated that under proper tuning conditions, the ultrasonic spray pyrolysis technique enables one to obtain glass-supported polycrystalline CeO2 films with noticeable texture along both the (100) and (111) directions, as well as with randomly oriented crystallites (no texture). The influence of flow rates, solution molarity, and substrate temperature on the texture and morphological characteristics, as well as optical absorption and Raman response of the deposited films, is evaluated. The obtained results are discussed on the basis of the combined dependence of the CeO2-exposed surfaces on the thermodynamic stability of the corresponding facets and the reaction kinetics, which modulate the crystallite growth direction.


2021 ◽  
Vol 44 (2) ◽  
Author(s):  
Ovier Obregon ◽  
José A Luna-Lopez ◽  
Pedro Rosales ◽  
Mario Moreno ◽  
Abdu Orduña-Diaz ◽  
...  

2015 ◽  
Vol 659 ◽  
pp. 252-256
Author(s):  
Sudarat Chaiwatyothin ◽  
Wittawat Ratanathavorn ◽  
Tharapong Vitidsant ◽  
Prasert Reubroycharoen

Synthesis of nanoCu/ZnO catalyst for LPG production was prepared by ultrasonic spray pyrolysis (USP). Hollow spherical particles were obtained by USP technique using an aqueous solution of Cu (NO3)3.6H2O and Zn (NO3)3.3H2O with different concentration of 0.05, 0.1 and 0.5 molar under the pyrolysis temperatures of 600, 700 and 800°C. Mists of the solution were generated from the precursor solution by ultra sonic vibrators at frequency of ~1.7 MHz. The physicochemical properties of catalysts were characterized by X-ray diffraction, temperature-programmed reduction, scanning electron microscope, nitrogen adsorption-desorption, and energy dispersive X-ray spectrometer. The results showed that increasing in precursor concentration resulted in a large particle and particles size distributed in a range of 0.63-1.21 μm. Particles prepared at pyrolysis temperature 700°C exhibited homogeneous in size and shape compared to other temperature. The catalytic activity of nanoCu/ZnO-Pd-β catalysts was performed in a fixed-bed reactor for synthesizing LPG. The reaction took place at 260°C, 3.0 MPa, and the ratio of H2/CO = 2/1. All the products from the reactor were in gaseous state, and analyzed by on-line gas chromatography. The results showed that %CO conversion was high but decreased rapidly with increasing reaction time. Cu/ZnO catalyst prepared by co-precipitation gave higher %CO conversion than that prepared by ultrasonic spray pyrolysis. Moreover, hydrocarbon product distribution for Cu/ZnO catalyst produced at concentration 0.1 M 700°C by ultrasonic spray pyrolysis gave the highest LPG selectivity.


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