Opportunistic use of tetrachloroaurate photolysis in the generation of reductive species for the production of gold nanostructures

McGilvray, Katherine L.; Granger, J.; Correia, M. R.; Banks, J. T.; Scaiano, Juan C.

doi:10.1039/c1cp20308h

Cited by 39 publications

(73 citation statements)

References 33 publications

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“…The photolysis mechanism may first involve the dissociation of AuCl 4 in water to generate AuCl 3 and a chlorine atom; the subsequent donation of hydrogen from sodium citrate can generate strongly reducing radicals, which can initiate the formation of Au NPs. 68 The much slower formation of Au NPs compared with previous work 68 is due to the weak UV emission from natural light. We note that the absorption of light by ZnO is also possible, which can potentially result in the generation of charge carriers that are active for the reduction of Au 3+ .…”

Section: ■ Results and Discussionmentioning

confidence: 95%

Hybrid Au/ZnO Hexagonal Pyramid Nanostructures: Preferred Growth on the Apexes of the Basal Plane than on the Tip

et al. 2015

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Nanoscale materials having size-and shape-dependent interactions with light provide flexible opportunities for harvesting solar energy. Photocatalysts based on semiconductor nanoparticles (NPs) have been the most effective materials for the conversion of light into chemical energy, the efficiency of which can be further enhanced by the incorporation of metallic NPs forming hybrid nanostructures. The structural parameters of not only constituent components but also the resultant hybrid nanostructures are critical for the optimization of photocatalytic performance of composite catalysts. Here we demonstrated the successful size control over ZnO hexagonal pyramids (HPs) for the first time. The smallest HPs showing the best photocatalytic properties were used for further Au attachment. Interestingly, we found that most of the Au NPs preferred to grow on the apexes of the basal plane. Very occasionally, Au NPs at the tip of ZnO HPs can be observed. The role of light in promoting the reduction of gold salt by sodium citrate was also revealed. Quantum mechanical calculations were used to explain the site-specific growth of Au on the surface of ZnO HPs. Enhanced degradation rates over organic dyes were found for Au/ZnO hybrids under both UV and visible light irradiation.

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Section: ■ Results and Discussionmentioning

confidence: 95%

Hybrid Au/ZnO Hexagonal Pyramid Nanostructures: Preferred Growth on the Apexes of the Basal Plane than on the Tip

et al. 2015

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“…22 According to previous results, the suggested mechanism of AuCl 4 − photolysis on LbL systems is presented below in reactions 5-10. 36 A similar approach is expected when using cysteine as a function of the thiol groups, which for NTs + HAuCl 4 samples occurs by way of the remaining groups for nanotubes synthesis.…”

Section: Systems Obtained and Characterizationmentioning

confidence: 89%

Nanostructured Systems Obtention Using LbL Self-Assembly or the Cysteine-Assisted Adsorption Method and Their Application as a Water Splitting Single Catalyst

Galvão¹,

Barreto²,

Soares³

et al. 2019

J. Braz. Chem. Soc.

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The present work evaluated the effect on charge transfer in functionalized TiO 2 nanostructured systems using different binders. We highlight the conditions required to form self-assembled systems by varying the number of layers, as well as by substituting them for an organic binder, cysteine. Additionally, we study the pH effect of the precursor solution (HAuCl 4 ) on gold nanoparticles (AuNPs) formation. The morphological characterization allowed us to determine the percentage of Au atoms on the surface of the synthesized nanoparticles. Inductively coupled plasma mass spectrometry (ICP-MS) analysis determined the amount of gold deposited on the TiO 2 surface, which ranged from 4.56 to 253.00 ng mm -2 depending on the system used. Based on Fourier-transform infrared spectroscopy (FTIR) and Raman analysis, it was possible to propose a photolysis mechanism for AuNP formation in accordance with the change in the binders. The different systems were subjected to hydrogen photogeneration by a water splitting process, resulting in 2.02 μmol cm -2 of hydrogen production for cysteine binder [Cys+HAuCl 4 -2.7]. There proved to be an excellent synergy between the morphological aspects, crystallinity, and stability of this arrangement.

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“…They explained the post-irradiation AuCl 4 ½ À reduction and SPR absorbance-peak growth by proposing that the H 2 O 2 produced during irradiation reduced the remaining AuCl 4 ½ À , in the presence of the existing AuNPs [19]. This hypothesis was developed further by Tibbetts et al [15], using previous work showing that H 2 O 2 reduces AuCl 4 ½ À in the presence of AuNPs via the reaction [58,59]…”

Section: Mechanisms Of [Aucl 4 ] à Reduction 31 Reactions Of Watermentioning

confidence: 96%

Au Nanoparticle Synthesis Via Femtosecond Laser-Induced Photochemical Reduction of [AuCl4]−

John¹,

Meader²,

MooreTibbetts³

2018

Photochemistry and Photophysics - Fundamentals to Applications

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Laser-assisted metallic nanoparticle synthesis is a versatile "green" method that has become a topic of active research. This chapter discusses the photochemical reaction mechanisms driving AuCl 4 ½ À reduction using femtosecond-laser irradiation, and reviews recent advances in Au nanoparticle size-control. We begin by describing the physical processes underlying the interactions between laser pulses and the condensed media, including optical breakdown and supercontinuum emission. These processes produce a highly reactive plasma containing free electrons, which reduce AuCl 4 ½ À , and radical species producing H 2 O 2 that cause autocatalytic growth of Au nanoparticles. Then, we discuss the reduction kinetics of AuCl 4 ½ À , which follow an autocatalytic rate law in which the first-and second-order rate constants depend on free electrons and H 2 O 2 availability. Finally, we explain strategies to control the size of gold nanoparticles as they are synthesized; including modifications of laser parameters and solution compositions.

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Opportunistic use of tetrachloroaurate photolysis in the generation of reductive species for the production of gold nanostructures

Cited by 39 publications

References 33 publications

Hybrid Au/ZnO Hexagonal Pyramid Nanostructures: Preferred Growth on the Apexes of the Basal Plane than on the Tip

Hybrid Au/ZnO Hexagonal Pyramid Nanostructures: Preferred Growth on the Apexes of the Basal Plane than on the Tip

Nanostructured Systems Obtention Using LbL Self-Assembly or the Cysteine-Assisted Adsorption Method and Their Application as a Water Splitting Single Catalyst

Au Nanoparticle Synthesis Via Femtosecond Laser-Induced Photochemical Reduction of [AuCl4]−

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