Bimetallic Au//Ag Alloys Inside SiO2 Using a Solid-State Method

Dı́az, Carlos; Valenzuela, Marı́a Luisa; Bobadilla, D.; Laguna‐Bercero, M. A.

doi:10.1007/s10876-017-1261-6

Cited by 4 publications

(8 citation statements)

References 17 publications

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“…On the other hand the XRD patterns diffraction for the composites Ag//SiO2 from both polymer precursors , see figure 3 (A) and (B), exhibits a similar peaks patterns to that of Au/SiO2 due to both Au and Ag they have a similar unitary cell 27 . Both XRD diffraction are in agreement with whose reported for another Ag//SiO2 composite prepared from solution 20,21 .…”

Section: -Results and Discussionmentioning

confidence: 78%

“…The method consists in the pyrolysis of the macromolecular precursors (Chitosan)•(MLn)n•(SiO2)m and (PS-co-4-PVP)•(MLn)n•(SiO2)m where the precursors (Chitosan)•(MLn)m and (PS-co-4-PVP)•(MLn)m are generated according previous reports [22][23][24][25][26] .Now, we use this approach to prepare Au° and Ag° inside SiO2 to give Au/SiO2 and Ag/SiO2 composites founding that the dispersion of the metal noble nanoparticles into the silica matrix can be controlled by the 1:1 or 1:5 metal/polymer ratio, as well as, by the nature of the polymer. The results are compared with those previously obtained 27 for bimetallic composites Au/Ag//SiO2. A preliminary work showing some of these result have been reported 27 .…”

Section: -Introductionmentioning

confidence: 78%

“…[22][23][24][25][26].and the SiO2 (prepared by sol-gel method see experiemental part and ref. 27,28) were mixture in solid state in a crucible and pyrolyzed under air at 800 °C. The composites were first characterized be powder XRD-ray diffraction.…”

Section: -Results and Discussionmentioning

confidence: 99%

“…SiO2 was prepared according a literature method 27,28 . Briefly, TEOS, ethanol, acetic acid in molar ratios 1:4:4 and water nanopure were stirring for 3 days.…”

Section: 3-sio2mentioning

confidence: 99%

“…Previously we have reported a versatile and reliable solid-state method to prepare metallic and metal oxides nanostructures materials [22][23][24][25][26] and their incorporation in SiO2 matrices 27,28 . The method consists in the pyrolysis of the macromolecular precursors (Chitosan)•(MLn)n•(SiO2)m and (PS-co-4-PVP)•(MLn)n•(SiO2)m where the precursors (Chitosan)•(MLn)m and (PS-co-4-PVP)•(MLn)m are generated according previous reports [22][23][24][25][26] .Now, we use this approach to prepare Au° and Ag° inside SiO2 to give Au/SiO2 and Ag/SiO2 composites founding that the dispersion of the metal noble nanoparticles into the silica matrix can be controlled by the 1:1 or 1:5 metal/polymer ratio, as well as, by the nature of the polymer.…”

Section: -Introductionmentioning

confidence: 99%

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Incorporation of Au and Ag Nanostructures Inside Sio2

Dı́az

Valenzuela

Soto

et al. 2019

J. Chil. Chem. Soc.

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Incorporation of Au° inside SiO2 was achieved by a solid-state method from the pyrolysis of the composites (Chitosan)•(AuCl3)n•(SiO2)m and (PS-co-4-PVP)•(AuCl3)n•(SiO2)m Similarly, the incorporation of Ag° inside SiO2 it was made from thermal treatment of the composites (Chitosan)•(AgNO3)n•(SiO2)m and (PS-co-4-PVP)•(AgNO3)n•(SiO2)m. The nature of the polymer controls the particle size for the Au/SiO2 composite, while that for the Ag/SiO2 both, polymer Chitosan and PS-co-4-PVP, produces similar particle size. In the case of the composite Ag/SiO2 the particle size as small as 5 nm were obtained.The 1:1 or 1:5 metal/polymer ratios, as well as the nature of the polymer in the macromolecular precursors (Chitosan)•(AuCl3)n•(SiO2)m and (PS-co-4-PVP)•(AuCl3)n•(SiO2)m influences the dispersion of the Au° nanostructures inside SiO2 matrix. The results are compared with those previously obtained for bimetallic composites Au/Ag//SiO2. A formation mechanism of the Au°/SiO2 and Ag°/SiO2 composites involving the combustion of the organic matter and the growth of the Au° and Ag° nanoparticles inside the holes, generated from the combustion process, is proposed.

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Section: -Results and Discussionmentioning

confidence: 78%

Section: -Introductionmentioning

confidence: 78%

Section: -Results and Discussionmentioning

confidence: 99%

“…SiO2 was prepared according a literature method 27,28 . Briefly, TEOS, ethanol, acetic acid in molar ratios 1:4:4 and water nanopure were stirring for 3 days.…”

Section: 3-sio2mentioning

confidence: 99%

Section: -Introductionmentioning

confidence: 99%

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Incorporation of Au and Ag Nanostructures Inside Sio2

Dı́az

Valenzuela

Soto

et al. 2019

J. Chil. Chem. Soc.

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Solid-State Preparation of Metal and Metal Oxides Nanostructures and Their Application in Environmental Remediation

Dı́az

Valenzuela

Laguna‐Bercero

2022

IJMS

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Nanomaterials have attracted much attention over the last decades due to their very different properties compared to those of bulk equivalents, such as a large surface-to-volume ratio, the size-dependent optical, physical, and magnetic properties. A number of solution fabrication methods have been developed for the synthesis of metal and metal oxides nanoparticles, but few solid-state methods have been reported. The application of nanostructured materials to electronic solid-state devices or to high-temperature technology requires, however, adequate solid-state methods for obtaining nanostructured materials. In this review, we discuss some of the main current methods of obtaining nanomaterials in solid state, and also we summarize the obtaining of nanomaterials using a new general method in solid state. This new solid-state method to prepare metals and metallic oxides nanostructures start with the preparation of the macromolecular complexes chitosan·Xn and PS-co-4-PVP·MXn as precursors (X = anion accompanying the cationic metal, n = is the subscript, which indicates the number of anions in the formula of the metal salt and PS-co-4-PVP = poly(styrene-co-4-vinylpyridine)). Then, the solid-state pyrolysis under air and at 800 °C affords nanoparticles of M°, MxOy depending on the nature of the metal. Metallic nanoparticles are obtained for noble metals such as Au, while the respective metal oxide is obtained for transition, representative, and lanthanide metals. Size and morphology depend on the nature of the polymer as well as on the spacing of the metals within the polymeric chain. Noticeably in the case of TiO2, anatase or rutile phases can be tuned by the nature of the Ti salts coordinated in the macromolecular polymer. A mechanism for the formation of nanoparticles is outlined on the basis of TG/DSC data. Some applications such as photocatalytic degradation of methylene by different metal oxides obtained by the presented solid-state method are also described. A brief review of the main solid-state methods to prepare nanoparticles is also outlined in the introduction. Some challenges to further development of these materials and methods are finally discussed.

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Incorporation of NiO into SiO2, TiO2, Al2O3, and Na4.2Ca2.8(Si6O18) Matrices: Medium Effect on the Optical Properties and Catalytic Degradation of Methylene Blue

et al. 2020

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The medium effect of the optical and catalytic degradation of methylene blue was studied in the NiO/SiO2, NiO/TiO2, NiO/Al2O3, and NiO/Na4.2Ca2.8(Si6O18) composites, which were prepared by a solid-state method. The new composites were characterized by XRD (X-ray diffraction of powder), SEM/EDS, TEM, and HR-TEM. The size of the NiO nanoparticles obtained from the PSP-4-PVP (polyvinylpyrrolidone) precursors inside the different matrices follow the order of SiO2 > TiO2 > Al2O3. However, NiO nanoparticles obtained from the chitosan precursor does not present an effect on the particle size. It was found that the medium effect of the matrices (SiO2, TiO2, Al2O3, and Na4.2Ca2.8(Si6O18)) on the photocatalytic methylene blue degradation, can be described as a specific interaction of the NiO material acting as a semiconductor with the MxOy materials through a possible p-n junction. The highest catalytic activity was found for the TiO2 and glass composites where a favorable p-n junction was formed. The isolating character of Al2O3 and SiO2 and their non-semiconductor behavior preclude this interaction to form a p-n junction, and thus a lower catalytic activity. NiO/SiO2 and NiO/Na4.2Ca2.8(Si6O18) showed a similar photocatalytic behavior. On the other hand, the effect of the matrix on the optical properties for the NiO/SiO2, NiO/TiO2, NiO/Al2O3, and NiO/Na4.2Ca2.8(Si6O18) composites can be described by the different dielectric constants of the SiO2, TiO2, Al2O3, Na4.2Ca2.8(Si6O18) matrices. The maxima absorption of the composites (λmax) exhibit a direct relationship with the dielectric constants, while their semiconductor bandgap (Eg) present an inverse relationship with the dielectric constants. A direct relationship between λmax and Eg was found from these correlations. The effect of the polymer precursor on the particle size can explain some deviations from this relationship, as the correlation between the particle size and absorption is well known. Finally, the NiO/Na4.2Ca2.8(Si6O18) composite was reported in this work for the first time.

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Bimetallic Au//Ag Alloys Inside SiO2 Using a Solid-State Method

Cited by 4 publications

References 17 publications

Incorporation of Au and Ag Nanostructures Inside Sio2

Incorporation of Au and Ag Nanostructures Inside Sio2

Solid-State Preparation of Metal and Metal Oxides Nanostructures and Their Application in Environmental Remediation

Incorporation of NiO into SiO2, TiO2, Al2O3, and Na4.2Ca2.8(Si6O18) Matrices: Medium Effect on the Optical Properties and Catalytic Degradation of Methylene Blue

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