Gold Nanoparticles for Oxidation Reactions: Critical Role of Supports and Au Particle Size

2020 ◽  
pp. 1-48
Author(s):  
Tamao Ishida ◽  
Ayako Taketoshi ◽  
Masatake Haruta
Keyword(s):  
Particle Size ◽  
Gold Nanoparticles ◽  
Critical Role ◽  
Oxidation Reactions ◽  
Au Particle Size

scholarly journals Thermal Atomic Layer Deposition of Gold Nanoparticles: Controlled Growth and Size Selection for Photocatalysis

2019 ◽  
Author(s):  
Fatemeh Sadat Minaye Hashemi ◽  
Fabio Grillo ◽  
Vikram Ravikumar ◽  
dominik Benz ◽  
Ankit Shekhar ◽  
...  
Keyword(s):  
Particle Size ◽  
Gold Nanoparticles ◽  
Atomic Layer Deposition ◽  
Au Nanoparticles ◽  
Atomic Layer ◽  
Structure Property ◽  
Structure Property Relationships ◽  
Layer Deposition ◽  
Catalytically Active ◽  
Au Particle Size

Gold nanoparticles have been extensively studied for their applications in catalysis. For Au nanoparticles to be catalytically active, controlling the particle size is crucial. Here we present a low temperature (105 °C) thermal atomic layer deposition approach for depositing gold nanoparticles on TiO<sub>2</sub> with controlled size and loading using trimethylphosphino-trimethylgold (III) and two co-reactants (ozone and water) in a fluidized bed reactor. We show that the exposure time of the precursors is a variable that can be used to decouple the Au particle size from the Au loading. Longer exposures of ozone narrow the particle size distribution while longer exposures of water broaden it. By studying the photocatalytic activity of Au/TiO<sub>2</sub> nanocomposites we show how the ability to control particle size and loading independently can be used not only to enhance performance but also to investigate structure-property relationships. This study provides insights into the mechanism underlying formation and evolution of Au nanoparticles via a vapor phase technique which eliminates the shortcomings of conventional liquid-base processes.

scholarly journals Diffractive arrays of gold nanoparticles near an interface: Critical role of the substrate

2010 ◽  
Vol 82 (15) ◽  
Author(s):  
Baptiste Auguié ◽  
Xesús M. Bendaña ◽  
William L. Barnes ◽  
F. Javier García de Abajo
Keyword(s):  
Gold Nanoparticles ◽  
Critical Role

scholarly journals Streptavidin-coated gold nanoparticles: critical role of oligonucleotides on stability and fractal aggregation

2017 ◽  
Vol 8 ◽  
pp. 1-11 ◽  
Author(s):  
Roberta D'Agata ◽  
Pasquale Palladino ◽  
Giuseppe Spoto
Keyword(s):  
Gold Nanoparticles ◽  
Critical Role ◽  
Medical Diagnostics ◽  
Nanoparticle Dispersion ◽  
One Dimensional ◽  
Fundamental Properties ◽  
Biochemical Sensing ◽  
Highly Sensitive ◽  
First Time

Gold nanoparticles (AuNPs) exhibit unique properties that can be modulated through a tailored surface functionalization, enabling their targeted use in biochemical sensing and medical diagnostics. In particular, streptavidin-modified AuNPs are increasingly used for biosensing purposes. We report here a study of AuNPs surface-functionalized with streptavidin-biotinylated oligonucleotide, focussing on the role played by the oligonucleotide probes in the stabilization/destabilization of the functionalized nanoparticle dispersion. The behaviour of the modified AuNP dispersion as a consequence of the competitive displacement of the biotinylated oligonucleotide has been investigated and the critical role of displaced oligonucletides in triggering the quasi one-dimensional aggregation of nanoparticles is demonstrated for the first time. The thorough understanding of the fundamental properties of bioconjugated AuNPs is of great importance for the design of highly sensitive and reliable functionalized AuNP-based assays.

Understanding the Role of Gold Nanoparticles in Enhancing the Catalytic Activity of Manganese Oxides in Water Oxidation Reactions

2014 ◽  
Vol 127 (8) ◽  
pp. 2375-2380 ◽  
Author(s):  
Chung-Hao Kuo ◽  
Weikun Li ◽  
Lakshitha Pahalagedara ◽  
Abdelhamid M. El-Sawy ◽  
David Kriz ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Catalytic Activity ◽  
Water Oxidation ◽  
Manganese Oxides ◽  
Oxidation Reactions

scholarly journals Glycerol Oxidation over Supported Gold Catalysts: The Combined Effect of Au Particle Size and Basicity of Support

Processes ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1016 ◽  
Author(s):  
Ekaterina Pakrieva ◽  
Ekaterina Kolobova ◽  
Dmitrii German ◽  
Marta Stucchi ◽  
Alberto Villa ◽  
...  
Keyword(s):  
Particle Size ◽  
Gold Nanoparticles ◽  
Alkaline Earth ◽  
Supported Catalysts ◽  
Combined Effect ◽  
Supported Gold Catalysts ◽  
Au Particle Size ◽  
Supported Gold ◽  
Determining Factor ◽  
Full Conversion

Gold nanoparticles supported on various oxides (CeO2, CeO2/TiO2, MgO, MgO/TiO2, La2O3, La2O3/TiO2) (with 4 wt.% Au loading) were investigated in the liquid (aqueous) phase oxidation of glycerol by molecular oxygen under mild conditions, in the presence of alkaline earth (CaO, SrO and MgO) or alkaline (NaOH) bases. Full conversion and selectivity between 38 and 68% to sodium glycerate were observed on different Au supported catalysts (Au/MgO/TiO2, Au/La2O3/TiO2, Au/CeO2 and Au/CeO2/TiO2). The combined effect of Au particle size and basicity of the support was suggested as the determining factor of the activity. Agglomeration of gold nanoparticles, found after the reaction, led to the deactivation of the catalysts, which prevents the further oxidation of sodium glycerate into sodium tartronate. Promising results were obtained with the use of alkaline earth bases (CaO, SrO, MgO), leading to the formation of free carboxylic acids instead of salts, which are formed in the presence of the more usual base, NaOH.

Synthesis of Silica Nanowires by Active Oxidation of Silicon Substrates

2006 ◽  
Vol 6 (3) ◽  
pp. 791-795 ◽  
Author(s):  
Andre S. Ferlauto ◽  
Sergio Oliveira ◽  
Edelma E. Silva ◽  
Rogerio Magalhaes-Paniago ◽  
Luiz O. Ladeira ◽  
...  
Keyword(s):  
Particle Size ◽  
Silicon Substrates ◽  
Oxidation Reactions ◽  
Si Substrate ◽  
Active Oxidation ◽  
Vapor Liquid Solid ◽  
Vapor Source ◽  
Ni Substrate ◽  
Silica Nanowires

Amorphous silica nanowires have been produced by thermal annealing of Si/SiO2/Ni substrate structures at 900 °C under an atmosphere of hexamethyldisilazane (HMDS) and hydrogen (H2). The wires have diameter ranging from 35 to 55 nm, which are controlled by the Ni particle size. It is demonstrated that the growth occurs through vapor–liquid–solid mechanisms, and it is proposed that the vapor source is volatile SiO generated from the etching of the Si substrate through active oxidation reactions. The role of the HMDS-H2 atmosphere in promoting such reactions is discussed.

Synthesis of Chitosan-Gold Nanoparticles for Drug Delivery

2014 ◽  
Vol 896 ◽  
pp. 280-283 ◽  
Author(s):  
Hanani Yazid ◽  
Amirah Mohd Yassin ◽  
Ahmad Zahid Ruslan ◽  
Siti Hajar Alias ◽  
Rohana Adnan ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Particle Size ◽  
Gold Nanoparticles ◽  
Environmental Remediation ◽  
Gold Salt ◽  
Au Nps ◽  
Chitosan Concentration ◽  
Wide Range ◽  
Potential Applications ◽  
Au Particle Size

Gold nanoparticles (Au NPs) have potential applications in catalysis, drug delivery, sensors and environmental remediation. This wide range application is due to its amenability of synthesis and functionalization, less toxicity and ease of detection. The present work focuses on functionalization of Au NPs with chitosan for further application in biomedical research. Gold nanoparticles (Au NPs) functionalized chitosan were prepared by reducing gold salt solution at various pH medium in the presence of sodium borohydride. The effect of pH and chitosan concentration on the Au particle size and distribution are studied. The results revealed the dependence of Au particle size on the pH of the solution. The smallest Au particle size is found to form in a range of 10.22 ± 2.96 nm at 0.2% chitosan concentration. In this study, we anticipate the Au NPs functionalized chitosan can be used for drug delivery applications.

Understanding the Role of Gold Nanoparticles in Enhancing the Catalytic Activity of Manganese Oxides in Water Oxidation Reactions

2014 ◽  
Vol 54 (8) ◽  
pp. 2345-2350 ◽  
Author(s):  
Chung-Hao Kuo ◽  
Weikun Li ◽  
Lakshitha Pahalagedara ◽  
Abdelhamid M. El-Sawy ◽  
David Kriz ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Catalytic Activity ◽  
Water Oxidation ◽  
Manganese Oxides ◽  
Oxidation Reactions

scholarly journals Thermal Atomic Layer Deposition of Gold Nanoparticles: Controlled Growth and Size Selection for Photocatalysis

2019 ◽  
Author(s):  
Fatemeh Sadat Minaye Hashemi ◽  
Fabio Grillo ◽  
Vikram Ravikumar ◽  
dominik Benz ◽  
Ankit Shekhar ◽  
...  
Keyword(s):  
Particle Size ◽  
Gold Nanoparticles ◽  
Atomic Layer Deposition ◽  
Au Nanoparticles ◽  
Atomic Layer ◽  
Structure Property ◽  
Structure Property Relationships ◽  
Layer Deposition ◽  
Catalytically Active ◽  
Au Particle Size

Gold nanoparticles have been extensively studied for their applications in catalysis. For Au nanoparticles to be catalytically active, controlling the particle size is crucial. Here we present a low temperature (105 °C) thermal atomic layer deposition approach for depositing gold nanoparticles on TiO<sub>2</sub> with controlled size and loading using trimethylphosphino-trimethylgold (III) and two co-reactants (ozone and water) in a fluidized bed reactor. We show that the exposure time of the precursors is a variable that can be used to decouple the Au particle size from the Au loading. Longer exposures of ozone narrow the particle size distribution while longer exposures of water broaden it. By studying the photocatalytic activity of Au/TiO<sub>2</sub> nanocomposites we show how the ability to control particle size and loading independently can be used not only to enhance performance but also to investigate structure-property relationships. This study provides insights into the mechanism underlying formation and evolution of Au nanoparticles via a vapor phase technique which eliminates the shortcomings of conventional liquid-base processes.

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