scholarly journals The Sintering of Au Nanoparticles on Flat {100}, {111} and Zigzagged {111}-Nanofacetted Structures of Ceria and Its Influence on Catalytic Activity in CO Oxidation and CO PROX

2020 ◽  
Author(s):  
O. S. Bezkrovnyi ◽  
P. Kraszkiewicz ◽  
W. Mista ◽  
L. Kepinski

Abstract The thermal stability of Au nanoparticles on ceria support of various morphology (nanocubes, nanooctahedra, and {111}-nanofacetted nanocubes) in oxidizing and reducing atmospheres was investigated by electron microscopy. A beneficial effect of the reconstruction of edges of ceria nanocubes into zigzagged {111}-nanofacetted structures on the inhibition of sintering of Au nanoparticles was shown. The influence of different morphology of Au particles on various ceria supports on the reducibility and catalytic activity in CO oxidation, and CO PROX of Au/ceria catalysts was also investigated and discussed. It was shown, that ceria nanocubes with flat {110} terminated edges are more suitable as a support for Au nanoparticles, used to catalyze CO oxidation, than zigzagged {111}- nanofacetted structures. Graphic Abstract

2019 ◽  
Vol 7 (18) ◽  
pp. 10980-10987 ◽  
Author(s):  
Xiaoqing Cao ◽  
Jun Zhou ◽  
Hongna Wang ◽  
Song Li ◽  
Wei Wang ◽  
...  

Abnormal thermal stability and high catalytic activity of sub-10 nm Au nanoparticles prepared by novel interfacial plasma electrolytic oxidation.


2021 ◽  
Vol 21 (3) ◽  
Author(s):  
Aleksandra Kozłowska ◽  
Adam Grajcar ◽  
Aleksandra Janik ◽  
Krzysztof Radwański ◽  
Ulrich Krupp ◽  
...  

AbstractAdvanced medium-Mn sheet steels show an opportunity for the development of cost-effective and light-weight automotive parts with improved safety and optimized environmental performance. These steels utilize the strain-induced martensitic transformation of metastable retained austenite to improve the strength–ductility balance. The improvement of mechanical performance is related to the tailored thermal and mechanical stabilities of retained austenite. The mechanical stability of retained austenite was estimated in static tensile tests over a wide temperature range from 20 °C to 200 °C. The thermal stability of retained austenite during heating at elevated temperatures was assessed by means of dilatometry. The phase composition and microstructure evolution were investigated by means of scanning electron microscopy, electron backscatter diffraction, X-ray diffraction and transmission electron microscopy techniques. It was shown that the retained austenite stability shows a pronounced temperature dependence and is also stimulated by the manganese addition in a 3–5% range.


1994 ◽  
Vol 119 (2) ◽  
pp. 223-240 ◽  
Author(s):  
Hak Soo Kim ◽  
Chae Ho Shin ◽  
Guy Bugli ◽  
Monique Bureau-Tardy ◽  
Gerald Djega-Mariadassou

2013 ◽  
Vol 750-752 ◽  
pp. 1919-1923 ◽  
Author(s):  
Guo Xian Zhou ◽  
Ming Wei Yuan ◽  
Lin Jiang ◽  
Ming Long Yuan ◽  
Hong Li Li

The laponite-poly (L-lactide) composite films are prepared by the method of solution blending with polylactide (PLA) and laponite. The result shows that the homogeneous and smooth composite film is prepared with 1, 4-dioxane. Thermogravimetry analysis (TG) and tensile strength studies demonstrate that the thermal stability and tensile strength are improved with the laponite added. The scanning electron microscopy (SEM) measurement indicates that the pores of composite films get uniform and network structure is more and more compact with compared to pure PLA film. The present study reveals that the laponite as a complexing agent can improve the mechanical properties and thermal stability of PLA.


2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Mashael Alshabanat ◽  
Amal Al-Arrash ◽  
Waffa Mekhamer

Polymer nanocomposites of polystyrene matrix containing 10% wt of organo-montmorillonite (organo-MMT) were prepared using the solution method with sonication times of 0.5, 1, 1.5, and 2 hours. Cetyltrimethylammonium bromide (CTAB) is used to modify the montmorillonite clay after saturating its surface with Na+ions. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to characterize the montmorillonite before and after modification by CTAB. The prepared nanocomposites were characterized using the same analysis methods. These results confirm the intercalation of PS in the interlamellar spaces of organo-MMT with a very small quantity of exfoliation of the silicate layers within the PS matrix of all samples at all studied times of sonication. The thermal stability of the nanocomposites was measured using thermogravimetric analysis (TGA). The results show clear improvement, and the effects of sonication time are noted.


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