Appearance of silicon dioxide contaminant on Pt-Rh catalyst surface exposed to oxygen at high temperature

1985 ◽  
Vol 4 (2) ◽  
pp. 159-162 ◽  
Author(s):  
M. Rubel
Keyword(s):  
High Temperature ◽  
Silicon Dioxide ◽  
Catalyst Surface ◽  
Rh Catalyst

Production of Nanosilica from Iron Tailing and Characterization

2011 ◽  
Vol 295-297 ◽  
pp. 282-285
Author(s):  
Feng Feng Li ◽  
Ming Xi Zhang ◽  
Yi Shen ◽  
Du Jiao ◽  
Gui Qin Hou ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
High Temperature ◽  
Silicon Dioxide ◽  
Chemical Deposition ◽  
Deposition Method ◽  
Analysis Techniques ◽  
Chemical Deposition Method ◽  
Ft Ir ◽  
Thermal Analysis Techniques ◽  
Amorphous Matter

Nanosilica was extracted from iron tailing by the chemical deposition method, involving pickling, filters washing, alkali dissolving of pickling dregs in high temperature, precipitating silica controlled by diluted acid and so on. The product has been studied by SEM, XRD, FT-IR, and thermal analysis techniques, etc. These study shows that the nanosilica is a kind of amorphous matter consists of hydrous silicon dioxide (97.076%) with small amount of sodium and aluminum trapped inside the Si–O network. The diameter of globular silica particles is 30-50 nm.

Aluminum Nitride Micro-Channels Grown via Metal Organic Vapor Phase Epitaxy for MEMs Applications

2007 ◽  
Vol 1040 ◽  
Author(s):  
L. E. Rodak ◽  
Sridhar Kuchibhatla ◽  
P. Famouri ◽  
Ting Liu ◽  
D. Korakakis
Keyword(s):  
High Temperature ◽  
Aluminum Nitride ◽  
Silicon Dioxide ◽  
Vapor Phase ◽  
High Energy ◽  
Vapor Phase Epitaxy ◽  
Micro Channel ◽  
Organic Vapor ◽  
Micro Channels ◽  
Metal Organic

AbstractAluminum nitride (AlN) is a promising material for a number of applications due to its temperature and chemical stability. Furthermore, AlN maintains its piezoelectric properties at higher temperatures than more commonly used materials, such as Lead Zirconate Titanate (PZT) [1, 2], making AlN attractive for high temperature micro and nano-electromechanical (MEMs and NEMs) applications including, but not limited to, high temperature sensors and actuators, micro- channels for fuel cell applications, and micromechanical resonators.This work presents a novel AlN micro-channel fabrication technique using Metal Organic Vapor Phase Epitaxy (MOVPE). AlN easily nucleates on dielectric surfaces due to the large sticking coefficient and short diffusion length of the aluminum species resulting in a high quality polycrystalline growth on typical mask materials, such as silicon dioxide and silicon nitride [3,4]. The fabrication process introduced involves partially masking a substrate with a silicon dioxide striped pattern and then growing AlN via MOVPE simultaneously on the dielectric mask and exposed substrate. A buffered oxide etch is then used to remove the underlying silicon dioxide and leave a free standing AlN micro-channel. The width of the channel has been varied from 5 ìm to 110 ìm and the height of the air gap from 130 nm to 800 nm indicating the stability of the structure. Furthermore, this versatile process has been performed on (111) silicon, c-plane sapphire, and gallium nitride epilayers on sapphire substrates. Reflection High Energy Electron Diffraction (RHEED), Atomic Force Microscopy (AFM), and Raman measurements have been taken on channels grown on each substrate and indicate that the substrate is influencing the growth of the AlN micro-channels on the SiO2 sacrificial layer.

scholarly journals Selective hydroformylation of alkyl acrylates using [2,2′-bis(dipyrrolylphosphinooxy)-1,1′-(±)-binaphthyl]/Rh catalyst: reversal of regioselectivity

RSC Advances ◽  
2017 ◽  
Vol 7 (24) ◽  
pp. 14816-14823 ◽  
Author(s):  
Xiao Shu ◽  
Haoran Liang ◽  
Qianhui Wu ◽  
Fanding Zhou ◽  
Xueli Zheng ◽  
...  
Keyword(s):  
High Temperature ◽  
Alkyl Acrylates ◽  
Alkyl Acrylate ◽  
Rh Catalyst

Deuterioformylation clarified the possible mechanism for the regioselectivity reversal of hydroformylation of alkyl acrylate at low and high temperature.

Oxidation of Pentatitanium Trisilicide (Ti5Si3) Powder at High Temperature

2016 ◽  
Vol 868 ◽  
pp. 38-42 ◽  
Author(s):  
Jun-Ichi Matsushita ◽  
Tatsuki Satsukawa ◽  
Naoya Iwamoto ◽  
Xiao Ling Wang ◽  
Jian Feng Yang ◽  
...  
Keyword(s):  
High Temperature ◽  
Silicon Dioxide ◽  
Oxidation Resistance ◽  
Surface Film ◽  
High Hardness ◽  
Mass Gain ◽  
Titanium Silicide ◽  
High Melting Point ◽  
Oxidation Resistant ◽  
Resistant Layer

The oxidation of pentatitanium trisilicide (Ti5Si3) powder at high temperature was investigated in order to determine the suitability of this ceramic material for advanced application in an oxidation atmosphere at high temperature. Titanium silicide has been attracted for years as an engineering ceramics due to its high hardness, high melting point, and good chemical stability. The samples were oxidized from 300 to 1000 °C for 1 to 5 h in air. The mass changes were measured to estimate the oxidation resistance of the sample. The mass gain of the sample oxidized at 1000 °C for 5 h was about 26 % of the theoretical oxidation mass change. The commercial powder, Ti5Si3 showed an excellent oxidation resistance at 1000 °C, because the surface film of both titanium dioxide and silicon dioxide formed by oxidation acted as an oxidation resistant layer.

scholarly journals Characterization of magnetic biochar amended with silicon dioxide prepared at high temperature calcination

2016 ◽  
Vol 34 (3) ◽  
pp. 597-604 ◽  
Author(s):  
Shams Ali Baig ◽  
Zimo Lou ◽  
Malik T. Hayat ◽  
Ruiqi Fu ◽  
Yu Liu ◽  
...  
Keyword(s):  
High Temperature ◽  
Silicon Dioxide ◽  
Environmental Remediation ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Sem Images ◽  
Magnetic Biochar ◽  
Ft Ir ◽  
High Temperature Calcination

AbstractCalcination is considered to increase the hardness of composite material and prevent its breakage for the effective applications in environmental remediation. In this study, magnetic biochar amended with silicon dioxide was calcined at high temperature under nitrogen environment and characterized using various techniques. X-ray diffraction (XRD) analysis revealed elimination of Fe3O4 peaks under nitrogen calcination and formation of Fe3Si and iron as major constituents of magnetic biochar-SiO2 composite, which demonstrated its superparamagnetic behavior (>80 A2·kg−1) comparable to magnetic biochar. Thermogravimetric analysis (TGA) revealed that both calcined samples generated higher residual mass (>96 %) and demonstrated better thermal stability. The presence of various bands in Fourier transform infrared spectroscopy (FT-IR) was more obvious and the elimination of H–O–H bonding was observed at high temperature calcination. In addition, scanning electron microscopy (SEM) images revealed certain morphological variation among the samples and the presence of more prominent internal and external pores, which then judged the surface area and pore volume of samples. Findings from this study suggests that the selective calcination process could cause useful changes in the material composites and can be effectively employed in environmental remediation measures.

Reduction of electron trapping in silicon dioxide by high‐temperature nitrogen anneal

1981 ◽  
Vol 52 (9) ◽  
pp. 5691-5695 ◽  
Author(s):  
S. K. Lai ◽  
D. R. Young ◽  
J. A. Calise ◽  
F. J. Feigl
Keyword(s):  
High Temperature ◽  
Silicon Dioxide ◽  
Electron Trapping

High-Temperature SiC MOSFET Gas Sensors

2004 ◽  
Vol 828 ◽  
Author(s):  
Kevin Matocha ◽  
Vinayak Tilak ◽  
Peter Sandvik ◽  
Jesse Tucker
Keyword(s):  
Silicon Carbide ◽  
High Temperature ◽  
Silicon Dioxide ◽  
Gas Sensors ◽  
Gate Dielectric ◽  
Low Cost ◽  
Metal Gate ◽  
Catalytic Metal ◽  
Combustion Exhaust

ABSTRACTDue to tightening restrictions on combustion exhaust emissions, low-cost sensors are desired for monitoring NOx production in high-temperature exhaust streams. This paper reports the characterization of Silicon Carbide MOSFET NO sensors for use in combustion exhaust monitoring. SiC depletion-mode MOSFETs were fabricated using a thermally-grown silicon dioxide gate dielectric and a Pt catalytic metal gate electrode. SiC MOSFET gas sensors were characterized at temperatures as high as 525°C in an ambient of synthetic air and NO (50–200 ppm) for 30 hours with no degradation.

scholarly journals Pembuatan dan uji aktivitas katalis htsc berbasis besi oksida

2018 ◽  
Vol 6 (3) ◽  
pp. 699
Author(s):  
Fitri Rumiani ◽  
S Subagjo
Keyword(s):  
High Temperature ◽  
Surface Area ◽  
Catalyst Surface ◽  
Catalyst Activity ◽  
Nitrate Solution ◽  
Fixed Bed ◽  
Great Influence ◽  
Temperature Shift ◽  
Fixed Bed Reactor ◽  
Preparation Procedure

High temperature shift conversion is a water gas shift reaction using water to produce carbon dioxide and hydrogen in high temperature (370-400oC). The aim of this research is examining the preparation procedure of HTSC catalyst. The catalyst made by Co-precipitation method of Fe and Cr nitrate solution with Na2CO3 as precipitating agent. The specific surface area of catalyst is determined by BET method. The crystal structure was analyzed by XRD method. The catalyst activity was evaluated in the fixed bed reactor on laboratory scale with 370oC and 1 atm. The result shows that the preparation procedure of HTSC ITB catalyst is reproducible. Based on the preparation procedure, calcinations temperature has a great influence to the catalyst surface area. The calcinations temperature at 300oC gave the highest catalyst surface area (198 m2/g), and it is comparable with the surface area claimed by Jennings (200 m2/g). The catalyst has also the highest activity by means of CO conversion resulted by the catalyst activity test (86%) which is larger than commercial catalyst conversion (81%)Keywords : Activity, Catalyst based on Fe/Cr, HTSC, Precipitation Abstrak High temperature shift conversion (HTSC) merupakan reaksi pergeseran CO menggunakan air menjadi CO2 dun H2 yang diselenggarakan pada temperatur tinggi (370-400oC). Penelitian ini bertujuan untuk mendapatkan resep dan prosedur pembuatan katalis HTSC. Katalis dibuat dengan metode kopresipitasi larutan garam nitrat dart Fe dan Cr dengan Na2CO3 sebagai senyawa pengendap. Untuk mengetahui keberhasilan penelitian ini, dilakukan penentuan luas permukaan, struktur kristal, dan aktivitas katalis yang kemudian dibandingkan dengan katalis komersial. Luas permukaan spesiftk diukur menggunakan metode BET, sedangkan struktur kristal dianalisis menggunakan XRD. Uji aktivitas katalis dilakukan dalam reaktor fixed bed skala laboratorium pada 370oC dan 1 atm. Hasil penelt.tian menunjukkan bahwa pelaksanaan prosedur pembuatan katalis HTSC ITB sudah dapat diulangi dengan hasil yang sama (reproducible). Berdasarkan prosedur tersebut, temperatur kalsinasi sangat berpengaruh terhadap lnas permukaan katalis. Dalam rentang temperatur yang dipelajari (300-400oC), kalsinasi pada temperatur 300oC menghasilkan katalis dengan luas permukaan paling tinggi yaitu 192-198 m2/g. Makin tinggi luas permukaan katalis yang dihasilkan, makin tinggi aktivitas katalis tersebut. Katalis dengan luas permukaan 192-198 m2/g menghasilkan aktivitas paling tinggi, konversi CO yang dihasilkan adalah 86 %, sedikit lebih besar dari konversi katalis komersial (81 %).Kata Kunci : Aktivitas, HTSC, Katalis berbasis Fe/Cr, Prespitasi

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