XPS analysis of oleylamine/oleic acid capped Fe3O4 nanoparticles as a function of temperature

2014 ◽  
Vol 303 ◽  
pp. 6-13 ◽  
Author(s):  
D. Wilson ◽  
M.A. Langell
2019 ◽  
Vol 15 (5) ◽  
pp. 893-909 ◽  
Author(s):  
Elena-Alina Moacă ◽  
Claudia Farcaş ◽  
Dorina Coricovac ◽  
Stefana Avram ◽  
Ciprian-Valentin Mihali ◽  
...  

2009 ◽  
Vol 94 (1) ◽  
pp. 012507 ◽  
Author(s):  
S. Wang ◽  
F. J. Yue ◽  
D. Wu ◽  
F. M. Zhang ◽  
W. Zhong ◽  
...  

2010 ◽  
Vol 64 (22) ◽  
pp. 2462-2464 ◽  
Author(s):  
Di Li ◽  
Deli Jiang ◽  
Min Chen ◽  
Jimin Xie ◽  
Yinyin Wu ◽  
...  

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Sharanabasava V. Ganachari ◽  
Veerabhadragouda B. Patil ◽  
Nagaraj R. Banapurmath ◽  
Manzoore Elahi M. Soudagar ◽  
Kiran Shahapurkar ◽  
...  

The aim of the present work is the synthesis and characterization of iron oxide (Fe3O4) nanoparticles. These nanoparticles are coated with oleic acid and polyvinyl butyral and mixed with microspheres and further developed ferrofluids with silicon oil. Studies of the performance of the nanoparticles in these ferrofluids with and without coating agents were carried out. The nanoparticles were synthesized using the chemical co-precipitation technique and coated with oleic acid and polyvinyl butyral, and it further mixed with microsphere ferrofluids and developed using silicon oil. The prepared Fe3O4 nanoparticles and their coated forms of oleic acid and polyvinyl butyral were mixed with microspheres; furthermore, ferrofluids were developed with silicon oil. All forms of these ferrofluids are characterized for morphology and phase purity (SEM, XRD, and FTIR). The iron oxide (Fe3O4) nanoparticles have shown different magnetic properties, differentiating macroscopic iron oxide in suspended particles. The ratio of surface to volume increases along with the decrease in atomic size, essential for assessing the surface morphological properties. The magneto-rheological (MR) fluids were determined, and shear stress of Expancel microsphere mixed iron oxide nanoparticle with and without them was found almost equal. However, the ferrofluid with PVB coated nanoparticles and microspheres emerged as a stable rheological ferrofluid, sustaining high shear stress and low viscosity with increasing shear rate. Also, shear rates up to 650 s−1 have been observed, showing very high shear stress withstanding capacity. The stability and performance of the magnetic colloidal ferrofluids depend on the thermal contribution and the balance between attractive/repulsive interactions.


2011 ◽  
Vol 364 ◽  
pp. 288-292 ◽  
Author(s):  
Nor Asikin Mohamad Nordin ◽  
Nadia Farhana Adnan ◽  
Noraini Hamzah ◽  
Wan Nor Roslam Wan Isahak ◽  
Alifee Ayatillah ◽  
...  

Different catalysts, namely various loading of perchloric acid on various supports; HClO4/silica (SiO2), HClO4/silica gel (SG) and HClO4/alumina (Al2O3) were tested for the direct addition reaction of oleic acid (OA) to form estolide compounds. The reactions were carried out under vacuum (2 mBar) for 10 hours at 70 °C under solvent-less conditions. LC-MS ToF of reaction products results showed chromatographic peaks for the presence of two new estolide compounds, oleic-oleic monoestolide acid (m/z563.51, as [M-H]-), and oleic-oleic diestolide acid (m/z845.77 [M-H]-). The optimum loading of HClO4for every support are 15 wt.% HClO4/SiO2(SiO215), 10 wt.% HClO4/SG (SG10) and 35 wt.% HClO4/Al2O3(Al2O335). The SG10 turned out to be the best catalyst, achieving a final conversion of 97.5 % with 79.8 % selectivity to oleic-oleic monoestolide acid and 17.7 % selectivity to oleic-oleic diestolide acid. The activity and selectivity of the SG10 have been investigated and compared with homogeneous HClO4. The optimum catalysts for every support were characterized by XPS analysis, BET, TEM and TPD-NH3.


2014 ◽  
Vol 153 (1) ◽  
pp. 92-101 ◽  
Author(s):  
Fei Wang ◽  
Chan Yin ◽  
Xiaoyi Wei ◽  
Qinghuang Wang ◽  
Lihong Cui ◽  
...  

2016 ◽  
Vol 171 ◽  
pp. 336-345 ◽  
Author(s):  
T.F. Marinca ◽  
H.F. Chicinaş ◽  
B.V. Neamţu ◽  
O. Isnard ◽  
P. Pascuta ◽  
...  

2020 ◽  
Vol 8 (15) ◽  
pp. 3087-3091
Author(s):  
Wei Liu ◽  
Guang Deng ◽  
Danli Wang ◽  
Ming Chen ◽  
Zhiguo Zhou ◽  
...  

Monodispersed hollow Fe3O4 nanoparticles with the diameters of 7 and 10 nm were prepared via a high-temperature pyrolysis method and the Kirkendall effect by regulating the ratio of oleylamine to oleic acid.


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