Computational Study of Pt/Co Core–Shell Nanoparticles: Segregation, Adsorbates and Catalyst Activity

2012 ◽  
Vol 116 (29) ◽  
pp. 15432-15438 ◽  
Author(s):  
M. Kettner ◽  
W. B. Schneider ◽  
A. A. Auer
Keyword(s):  
Computational Study ◽  
Catalyst Activity ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Core Shell Nanoparticles

scholarly journals Stabilizing Highly Dispersed Halo Sites in Thermally Restructured Palladium Core@shell Nanoparticles for Improved Catalyst Activity and Durability

2021 ◽  
Author(s):  
Alexander Hill ◽  
Adarsh Bhat ◽  
Zachary Berquist ◽  
Galen Fisher ◽  
Andrej Lenert ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Catalyst Activity ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Highly Dispersed ◽  
Catalytically Active ◽  
Metal Support ◽  
The Stability ◽  
Material Utilization ◽  
Core Shell Nanoparticles

Stabilizing high dispersions of catalytically active metals is integral to improving the lifetime, activity, and material utilization of catalysts that are periodically exposed to high temperatures during operation or maintenance. We have found that annealing palladium-based core@shell catalysts in air at elevated temperature (800°C) promotes the redispersion of active metal into highly dispersed sites, which we refer to as halo sites. Here, we examine the restructuring of Pd@SiO2 and Pd@CeO2 core@shell catalysts over successive 800°C aging cycles to understand the formation, activity, nanoscale structure and stability of these palladium halo sites. While encapsulation generally improves metal utilization by providing a physical barrier that promotes redispersion over agglomeration, our cycled aging experiments demonstrate that halo sites are not stable in all catalysts. Halo sites continue to migrate in Pd@SiO2 due to poor metal-support bonding, which leads to palladium agglomeration. In contrast, halo sites formed in Pd@CeO2 remain stable. The dispersed palladium also synergistically stabilizes the ceria from agglomerating. We attribute this stability, in addition to an observed improvement in catalytic activity, to the coordination between palladium and reducible ceria that arises during the formation of halo sites. We probe the importance of ceria oxidation state on the stability of halo sites by aging Pd@CeO2 after it has been reduced. While some halo sites agglomerate, we find that returning to air aging mitigates the loss of these sites and catalytic activity. Our findings illustrate how nanoscale catalyst structures can be designed to promote the formation of highly stable and dispersed metal sites.

Preparation and Electrocatalytic Performance of Thin-shell Ni/Pt Core-shell Nanoparticles

2012 ◽  
Vol 27 (1) ◽  
pp. 95-101
Author(s):  
Shi-Bin LIU ◽  
Chun-Ying YANG ◽  
Zhong-Lin ZHANG ◽  
Dong-Hong DUAN ◽  
Xiao-Gang HAO ◽  
...  
Keyword(s):  
Thin Shell ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Electrocatalytic Performance ◽  
Core Shell Nanoparticles

Pluronic-Based Core/Shell Nanoparticles for Drug Delivery and Diagnosis

2013 ◽  
Vol 20 (28) ◽  
pp. 3488-3499 ◽  
Author(s):  
Yon Jung ◽  
Hwanbum Lee ◽  
Jae Kim ◽  
Eun Koo ◽  
Keun Oh ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Core Shell Nanoparticles

Colorimetric and SERS dual-mode sensing of mercury (II) based on controllable etching of Au@Ag core/shell nanoparticles

2021 ◽  
Vol 330 ◽  
pp. 129364
Author(s):  
Jinhua Wang ◽  
Jiamin Wu ◽  
Yuping Zhang ◽  
Xia Zhou ◽  
Ziwei Hu ◽  
...  
Keyword(s):  
Core Shell ◽  
Dual Mode ◽  
Shell Nanoparticles ◽  
Core Shell Nanoparticles
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