Study on selective oxidations of gold nanorod and mesoporous silica-coated gold nanorod

Wu, Zihua; Liang, Yuling; Guo, Qing; Zhang, Keqiu; Liang, Shifang; Yang, Liyun; Xiao, Qi; Wang, Dan

doi:10.1007/s10853-019-03429-4

Cited by 10 publications

(10 citation statements)

References 49 publications

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“…In water, silica shells could not withstand etching without heat treatment. The silica wall shrunk when treated in hot water and then in room-temperature KCN (aq), similar to those reported in the literature. , When etching was carried out in pure MeOH, silica shells did not shrink. , After etching AuNR@mSiO 2 without heat treatment, Au was uniformly etched away in KCN (aq), leading to the blue-shifted LSPR (Figure A,B). Blue-shifted LSPR results were also observed with AuNR@mSiO 2 after etching in pure MeOH without heat treatment (Figure C).…”

Section: Resultssupporting

confidence: 86%

“…In addition to opening the pores uniformly or selectively, heat treatment has another function, which is to harden the silica nanoshells, especially when etching was performed in alcoholic solvents. 32,42 3.3.1. Etching without Heat Treatment (for Comparison Purpose).…”

Section: Heat Treatment Of Aunr@msio 2 (Secondmentioning

confidence: 99%

“…This trend matches the outcome of the trend reported in literature. 32,42,43,51 The absorbance decreased due to the diminished amount of Au over the course of etching. Nearly, a 200 nm blue shift was observed (Figure 4B).…”

Section: Etching After Heat Treatment In Svsmentioning

confidence: 99%

“…16 Another way to control the etching was to use hard shell coating such as mesoporous silica, which showed mostly a blue shift of the LSPR. 32,42,43 TEM was used to monitor the pores of the mesoporous shells in such etching and when the pores were more open, etching was more efficient. 42 The products of BUTTONS can be used in many applications.…”

Section: Introductionmentioning

confidence: 99%

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Bottom-Up Then Top-Down Synthesis of Gold Nanostructures Using Mesoporous Silica-Coated Gold Nanorods

Peck,

Lien,

et al. 2023

ACS Omega

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Gold nanostructures were synthesized by etching away gold from heattreated mesoporous silica-coated gold nanorods (AuNR@mSiO 2 ), providing an example of top-down modification of nanostructures made using bottom-up methodology. Twelve different types of nanostructures were made using this bottom-up-then-top-down synthesis (BUTTONS), of which the etching of the same starting nanomaterial of AuNR@mSiO 2 was found to be controlled by how AuNR@ mSiO 2 were heat treated, the etchant concentration, and etching time. When the heat treatment occurred in smooth moving solutions in round-bottomed flasks, red-shifted longitudinal surface plasmon resonance (LSPR) was observed, on the order of 10−30 min, indicating increased aspect ratios of the gold nanostructures inside the mesoporous silica shells. When the heat treatment occurred in turbulent solutions in scintillation vials, a blue shift of the LSPR was obtained within a few minutes or less, resulting from reduced aspect ratios of the rods in the shells. The influence of the shape of the glassware, which may impact the flow patterns of the solution, on the heat treatment was investigated. One possible explanation is that the flow patterns affect the location of opened pores in the mesoporous shells, with the smooth flow of solution mainly removing CTAB surfactants from the pores along the cylindrical body of mSiO 2 , therefore increasing the aspect ratios after etching, and the turbulent solutions removing more surfactants from the pores of the two ends or tips of the silica shells, hence decreasing the aspect ratios after etching. These new stable gold nanostructures in silica shells, bare and without surfactant protection, may possess unique chemical properties and capabilities. Catalysis using heat-treated nanomaterials was studied as an example of potential applications of these nanostructures.

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Section: Resultssupporting

confidence: 86%

Section: Heat Treatment Of Aunr@msio 2 (Secondmentioning

confidence: 99%

Section: Etching After Heat Treatment In Svsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Bottom-Up Then Top-Down Synthesis of Gold Nanostructures Using Mesoporous Silica-Coated Gold Nanorods

Peck,

Lien,

et al. 2023

ACS Omega

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show abstract

“…Gold seeds were prepared as previously reported with slight modification. 13,39,40 In a 30 °C water bath, 1.0 mL of 0.01 M HAuCl 4 •4H 2 O was thoroughly mixed with 18.0 mL of 0.1 M CTAB solution. Under vigorous stirring, 1.0 mL of NaBH4 solution prepared by dissolving 11.3 mg NaBH 4 in 20 mL ice cold water was quickly injected to the mixture.…”

Section: Synthesis Of Gold Seedsmentioning

confidence: 99%