scholarly journals Formation of silver nanoparticles on lignin and two of its precursors

Les/Wood ◽  
2021 ◽  
Vol 70 (1) ◽  
Author(s):  
Sebastian Dahle ◽  
Lienhard Wegewitz ◽  
Wolfgang Viöl ◽  
Wolfgang Maus-Friedrichs

Metastable Induced Electron Spectroscopy, Ultraviolet Photoelectron Spectroscopy (He I and He II), X-ray Photoelectron Spectroscopy, and Atomic Force Microscopy were employed to study the interaction of silver with lignin as well as with two of its natural precursors, coniferyl alcohol and sinapyl alcohol. For all three of them, no chemical interaction between the adsorbed silver and the organic substrate was found before contact with air. Nevertheless, silver nanoparticles were found in all three cases after contact with air. Thus, a process of silver nanoparticle formation during the decomposition of the organic molecules is suggested, similar to the previously found catalytic decomposition of cinnamyl alcohol by water in the presence of silver atoms.

2006 ◽  
Vol 6 (3) ◽  
pp. 748-755 ◽  
Author(s):  
M. Sendova ◽  
M. Sendova-Vassileva ◽  
J. C. Pivin ◽  
H. Hofmeister ◽  
K. Coffey ◽  
...  

Thin films of silica containing silver nanoparticles were deposited by magnetron co-sputtering followed by thermal annealing in air or Ar + 2% H2. Laser fragmentation of the particles was carried out at two different wavelengths. The films were characterized by UV-VIS absorption spectroscopy and plasmon resonance numerical modeling based on the Mie theory, together with Rutherford backscattering elemental analysis, X-ray photoelectron spectroscopy chemical characterization, combined with statistical analysis of the transmission electron microscopy micrographs, and surface topography study by atomic force microscopy. It is demonstrated that the fragmentation is a result of a thermal process and its mechanism does not depend on the laser wavelength as long as the laser light is absorbed by the silver particles. Laser treatment with moderate fluences does not alter the precipitated metal content while fragmenting the particles. TEM study indicates that laser assisted silver particle modification can serve as a method for narrowing the particle size distribution.


Nanomaterials ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 780 ◽  
Author(s):  
Ana Patrícia Carapeto ◽  
Ana Maria Ferraria ◽  
Ana Maria Botelho do Rego

In this work, cellulose films pre-activated with carbonyldiimidazole (CDI) and grafted with 1,6-hexanediamine, were decorated with silver nanoparticles (AgNPs). The generation of AgNPs was followed by quartz crystal microbalance (QCM). The obtained films were characterized by X-Ray Photoelectron Spectroscopy (XPS) and imaged by atomic force microscopy (AFM). XPS confirmed the synthesis in situ of AgNPs on the film attesting their oxidation state. The results from the three techniques were compared showing how sound the quantitative treatment of the results issued from these techniques can be. The main objective of this work is exactly to show that the quantitative exploration of the results of different characterization techniques can and should be practiced systematically instead of just comparing them qualitatively.


Author(s):  
Замир Валериевич Шомахов ◽  
Светлана Сергеевна Налимова ◽  
Рустам Мухамедович Калмыков ◽  
Кирилл Аубекеров ◽  
Вячеслав Алексеевич Мошников

Слои диоксида олова синтезированы гидротермальным методом из водного раствора SnF. Наночастицы серебра осаждены на поверхность полученных слоев методом фотовосстановления. Проведено исследование морфологии поверхности образцов методом атомно-силовой микроскопии. Размер наночастиц серебра зависит от концентрации раствора AgNO, используемого для проведения реакции фотовосстановления. При синтезе из раствора с концентрацией 0,02 М размер полученных наночастиц составляет варьируется от 10 до 100 нм, при увеличении концентрации раствора в два раза размер наночастиц составляет порядка 100 нм. С помощью рентгеновской фотоэлектронной спектроскопии изучен состав поверхности слоев до и после осаждения наночастиц серебра. При выбранных условиях синтеза формируется слой диоксида олова без посторонних включений, и происходит осаждение металлического серебра. Химический сдвиг пиков олова и кислорода после осаждения наночастиц серебра свидетельствует об обмене электронами между оловом и серебром. Полученные слои представляют интерес для применения в области полупроводниковых адсорбционных газовых сенсоров. Tin dioxide layers were synthesized by hydrothermal method from an aqueous solution of SnF. Silver nanoparticles were deposited on the surface of the obtained layers by the photoreduction method. The surface morphology of the samples was studied by atomic force microscopy. The size of the silver nanoparticles depends on the concentration of the AgNO solution used for the photoreduction reaction. When synthesized from 0,02 M solution with a concentration of, the size of the nanoparticles varies from 10 to 100 nm, when the concentration of the solution is doubled, the size of the nanoparticles is about 100 nm. The surface composition of the layers before and after the deposition of silver nanoparticles was studied using the X-ray photoelectron spectroscopy. It was shown that a layer of the tin dioxide is formed without external inclusions, and metallic silver is deposited. The chemical shift of the peaks of tin and oxygen after the deposition of silver nanoparticles indicates the exchange of electrons between tin and silver. The synthesized layers are of interest for application in the field of semiconductor adsorption gas sensors.


2003 ◽  
Vol 780 ◽  
Author(s):  
C. Essary ◽  
V. Craciun ◽  
J. M. Howard ◽  
R. K. Singh

AbstractHf metal thin films were deposited on Si substrates using a pulsed laser deposition technique in vacuum and in ammonia ambients. The films were then oxidized at 400 °C in 300 Torr of O2. Half the samples were oxidized in the presence of ultraviolet (UV) radiation from a Hg lamp array. X-ray photoelectron spectroscopy, atomic force microscopy, and grazing angle X-ray diffraction were used to compare the crystallinity, roughness, and composition of the films. It has been found that UV radiation causes roughening of the films and also promotes crystallization at lower temperatures.Furthermore, increased silicon oxidation at the interface was noted with the UVirradiated samples and was shown to be in the form of a mixed layer using angle-resolved X-ray photoelectron spectroscopy. Incorporation of nitrogen into the film reduces the oxidation of the silicon interface.


Nanomedicine ◽  
2022 ◽  
Author(s):  
Hossein Danafar ◽  
Marziyeh Salehiabar ◽  
Murat Barsbay ◽  
Hossein Rahimi ◽  
Mohammadreza Ghaffarlou ◽  
...  

Aim: To prepare a novel hybrid system for the controlled release and delivery of curcumin (CUR). Methods: A method for the ultrasound-assisted fabrication of protein-modified nanosized graphene oxide-like carbon-based nanoparticles (CBNPs) was developed. After being modified with bovine serum albumin (BSA), CUR was loaded onto the synthesized hybrid (labeled CBNPs@BSA–CUR). The structure and properties of the synthesized nanoparticles were elucidated using transmission electron microscopy (TEM), atomic force microscopy (AFM), ultraviolet-visible spectroscopy (UV-Vis), Fourier-transform infrared spectroscopy (FTIR) and x-ray photoelectron spectroscopy (XPS) methods. Results: CBNPs@BSA–CUR showed pH sensitivity and were calculated as controlled CUR release behavior. The drug-free system exhibited good biocompatibility and was nontoxic. However, CBNPs@BSA–CUR showed acceptable antiproliferative ability against MCF-7 breast cancer cells. Conclusion: CBNPs@BSA–CUR could be considered a highly promising nontoxic nanocarrier for the delivery of CUR with good biosafety.


2021 ◽  
Vol 314 ◽  
pp. 302-306
Author(s):  
Quoc Toan Le ◽  
E. Kesters ◽  
M. Doms ◽  
Efrain Altamirano Sánchez

Different types of ALD Ru films, including as-deposited, annealed Ru, without and with a subsequent CMP step, were used for wet etching study. With respect to the as-deposited Ru, the etching rate of the annealed Ru film in metal-free chemical mixtures (pH = 7-9) was found to decrease substantially. X-ray photoelectron spectroscopy characterization indicated that this behavior could be explained by the presence of the formation of RuOx (x = 2,3) caused by the anneal. A short CMP step applied to the annealed Ru wafer removed the surface RuOx, at least partially, resulting in a significant increase of the etching rate. The change in surface roughness was quantified using atomic force microscopy.


2018 ◽  
Vol 51 (2) ◽  
pp. 246-253
Author(s):  
Dev Raj Chopra ◽  
Justin Seth Pearson ◽  
Darius Durant ◽  
Ritesh Bhakta ◽  
Anil R. Chourasia

2013 ◽  
Vol 28 (2) ◽  
pp. 68-71 ◽  
Author(s):  
Thomas N. Blanton ◽  
Debasis Majumdar

In an effort to study an alternative approach to make graphene from graphene oxide (GO), exposure of GO to high-energy X-ray radiation has been performed. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM) have been used to characterize GO before and after irradiation. Results indicate that GO exposed to high-energy radiation is converted to an amorphous carbon phase that is conductive.


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