The Stabilization of Supported Au Nanoparticles in a Highly Sintering Environment using High Surface Free Energy Pt and Ru Cores

2021 ◽  
Author(s):  
Kerry O-Connell ◽  
John R Monnier ◽  
John Regalbuto
Keyword(s):  
Gold Nanoparticles ◽  
Free Energy ◽  
Surface Free Energy ◽  
Au Nanoparticles ◽  
High Surface ◽  
Chemical Environment ◽  
Core Shell

In an effort to stabilize gold nanoparticles which sinter rapidly in a highly corrosive chemical environment, the hydrochlorination of acetylene, bimetallic Ru@Au and Pt@Au core-shell catalysts were prepared by anchoring...

scholarly journals Design of gold nanoparticles-decorated SiO2@TiO2 core/shell nanostructures for visible light-activated photocatalysis

RSC Advances ◽  
2017 ◽  
Vol 7 (13) ◽  
pp. 7469-7475 ◽  
Author(s):  
Ryeri Lee ◽  
Yogeenth Kumaresan ◽  
Sei Young Yoon ◽  
Soong Ho Um ◽  
Il Keun Kwon ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Titanium Dioxide ◽  
Visible Light ◽  
Silicon Dioxide ◽  
Au Nanoparticles ◽  
Core Shell ◽  
Photocatalytic Reaction ◽  
Shell Nanostructures ◽  
Visible Light Driven

In this study, we designed core/shell nanostructures (CSNs) of silicon dioxide (SiO2)/titanium dioxide (TiO2), which were decorated with gold (Au) nanoparticles (NPs), to activate the visible light-driven photocatalytic reaction.

Biopolymer Blends as Potential Biomaterials and Cosmetic Materials

2013 ◽  
Vol 583 ◽  
pp. 95-100 ◽  
Author(s):  
Alina Sionkowska ◽  
Katarzyna Lewandowska ◽  
A. Planecka ◽  
P. Szarszewska ◽  
K. Krasinska ◽  
...  
Keyword(s):  
Contact Angle ◽  
Free Energy ◽  
Surface Free Energy ◽  
Silk Fibroin ◽  
High Surface ◽  
Force Microscopy ◽  
Angle Measurements ◽  
Atomic Force ◽  
Polymeric Blends ◽  
Contact Angle Measurements

Blends of two polymer, namely chitosan with silk fibroin or partially hydrolysed polyacrylamide (HPAM) were prepared. The surface properties of chitosan/silk fibroin and chitosan/HPAM blended films were investigated using the technique of Atomic Force Microscopy (AFM) and by means of contact angle measurements allowing the calculation of surface free energy. Measurements of the contact angle for diiodomethane (D), and glycerol (G) on the surface of chitosan films and chitosan/silk fibroin films were made and surface free energy was calculated. It was found that chitosan/silk fibroin blend surface is enriched in high surface energy component i.e. silk fibroin. The surface roughness of chitosan, silk fibroin, HPAM, chitosan/silk fibroin and chitosan/HPAM blended films differs with the composition of the blend. Film-forming polymeric blends can be potentially used as biomaterials and cosmetic materials.

Influence on Friction Force of Adhesion Force between Vulcanizates and Sliders

1994 ◽  
Vol 67 (5) ◽  
pp. 797-805 ◽  
Author(s):  
Kunio Mori ◽  
Satoshi Kaneda ◽  
Kentaro Kanae ◽  
Hidetoshi Hirahara ◽  
Yoshiyuki Oishi ◽  
...  
Keyword(s):  
Free Energy ◽  
Surface Free Energy ◽  
Friction Force ◽  
Coefficient Of Friction ◽  
Adhesion Force ◽  
High Surface ◽  
Low Surface Energy ◽  
Polar Groups ◽  
Slider Surface ◽  
The Coefficient Of Friction

Abstract The effects of vulcanizate and slider surface free energy—as well as the adhesion force (P) between them—on friction the force (F) and the coefficient of friction (μ) has been investigated. SBR and NBR vulcanizates were prepared using three molds differing in surface free energy. The mold with a high surface free energy gave a vulcanizate surface possessing polar groups. The mold with low surface energy gave a vulcanizate surface with many nonpolar groups. The coefficient of friction increased with the surface free energy of SBR and NBR vulcanizates. With SBR vulcanizate (surface free energy, 31.3 mJ·m−2) and teflon slider (surface free energy, 28.1 mJ·m−2) combination having the least surface free energy, the coefficient of friction was constant at greater than a 0.2N load. With vulcanizates and an aluminum slider with high surface free energy, friction force could be detected even at zero load because of the adhesion force at the interface. Friction force increased linearly with adhesion force between vulcanizates and sliders when the physical properties of the vulcanizates and net work chain density were constant. The present results clearly demonstrate the contribution of adhesion force to the friction of vulcanizates.

scholarly journals X-ray powder diffraction to analyse bimetallic core–shell nanoparticles (gold and palladium; 7–8 nm)

RSC Advances ◽  
2019 ◽  
Vol 9 (46) ◽  
pp. 26628-26636 ◽  
Author(s):  
A. Rostek ◽  
K. Loza ◽  
M. Heggen ◽  
M. Epple
Keyword(s):  
Gold Nanoparticles ◽  
Diffraction Study ◽  
Powder Diffraction ◽  
Au Nanoparticles ◽  
Vinyl Pyrrolidone ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
X Ray ◽  
Shell Nanostructures ◽  
Core Shell Nanoparticles

A comparative X-ray powder diffraction study on poly(N-vinyl pyrrolidone) (PVP)-stabilized palladium and gold nanoparticles and bimetallic Pd–Au nanoparticles (both types of core–shell nanostructures) was performed.

Formation of Surface Structure in Vulcanizates and Surface Structure Changes in Air

1995 ◽  
Vol 68 (1) ◽  
pp. 97-109 ◽  
Author(s):  
Kunio Mori ◽  
Kentaro Kanae ◽  
Hidetoshi Hirahara ◽  
Yoshiyuki Oishi
Keyword(s):  
Free Energy ◽  
Surface Structure ◽  
Surface Free Energy ◽  
High Surface ◽  
Surface Region ◽  
Interfacial Free Energy ◽  
Chemical Compositions ◽  
Free Energies ◽  
Dry Air ◽  
Structure Changes

Abstract The formation theory of surface structure during vulcanization was developed on the basis of an interfacial concept. The theory showed the chemical compositions of polar and nonpolar components on the vulcanizate surface to be determined as an excess interfacial free energy between rubber compounds and molds decreases. The surface free energies of molds reflected clearly the corresponding surface free energy of vulcanizates prepared from copolymers and polar polymers. Nonpolar polymers were not influenced by the surface free energies of molds. The surface free energies of vulcanizates decreased slightly with the concentration of network chains owing to the entropy of rubber segments. The surface free energies of molds affected the chemical compositions at the topmost surface region to the upper surface region on vulcanizates. NBR vulcanizates with high surface free energy increased the contact angle of water after standing in dry air. In the dry air environment, topmost surface layer nitrile groups were buried in the bulk of NBR vulcanizates and butadiene units subsequently overturn to the topmost, layer. In this case, the vulcanizate surface chemical composition was influenced only at the topmost surface region. ESCA spectra N1s peak intensities on NBR vulcanizates was consistent with these observation.

Influence of Molecular Ordering on Surface Free Energy of Polymer Nanofibres using Scanning Probe Microscopy

2007 ◽  
Vol 1025 ◽  
Author(s):  
Shuangwu Li ◽  
Wei Wang ◽  
Asa H Barber
Keyword(s):  
Free Energy ◽  
Surface Free Energy ◽  
Scanning Probe Microscopy ◽  
High Surface ◽  
Electrospinning Process ◽  
Scanning Probe ◽  
Fibrous Materials ◽  
Bulk Polymer ◽  
Probe Microscopy ◽  
Molecular Ordering

AbstractFibrous materials are used in a variety of applications due to their relatively high surface area to volume as well as anisotropic behavior. Electrospinning is a popular fabrication method which produces polymer nanofibres with a potentially high molecular alignment. In this work we examine the surface free energy of electrospun polyvinyl-alcohol nanofibres and its relation to molecular ordering using scanning probe microscopy adhesion measurements. Comparisons are made with bulk polymer material to show that a high degree of molecular orientation is present at least at the surface of the polymer nanofibre. As a result, the surface free energy of electrospun polymer nanofibres is greater than that of a bulk polymer. This effect indicates that the electrospinning process is effective at polymer alignment over a variety of experimental parameters.

Synthesis of a hollow structured core–shell Au@CeO2–ZrO2 nanocatalyst and its excellent catalytic performance

2017 ◽  
Vol 5 (11) ◽  
pp. 5601-5611 ◽  
Author(s):  
Chenhao Du ◽  
Yun Guo ◽  
Yanglong Guo ◽  
Xue-Qing Gong ◽  
Guanzhong Lu
Keyword(s):  
Surface Area ◽  
Au Nanoparticles ◽  
High Surface ◽  
High Surface Area ◽  
Catalytic Performance ◽  
Core Shell ◽  
Deposition Method ◽  
Hollow Core ◽  
Excellent Catalytic Performance ◽  
Ultrathin Layer

We proposed a hard-templated and electrostatic attraction induced deposition method to prepare a hollow core–shell Au@CeO2–ZrO2 nanocatalyst with a high surface area, in which a 6–8 nm ultrathin layer composed of CeO2–ZrO2 nanocrystals is embedded with individual Au nanoparticles, forming a sub-10 nm core–shell-like structure.

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