Papers by Gerardo Antonio Rosas Trejo
Microscopy and Microanalysis, 2020
Recently, the synthesis of silver nanoparticles (Nps) has been of great interest due to their opt... more Recently, the synthesis of silver nanoparticles (Nps) has been of great interest due to their optical, chemical and catalytic properties, which depend on their shape, size and chemical composition . However, to take advantage of its biomedical properties, it is necessary to use synthetic methods free of toxic chemicals. For this reason, green methods have been developed that consist of using plant extracts that contain active substances such as reducing agents and stabilizing agents .
The nanoparticles (NPs) of noble metals present great interest due to their properties and as a c... more The nanoparticles (NPs) of noble metals present great interest due to their properties and as a consequence of their wide variety of applications in which they are actively used. In the nanometric scale, the properties of nanoparticles improve with respect to their micrometric counterparts, which is why they have become essential for their study in biosensors, electrocatalysis, and optical applications. Nanoparticles are not only studied due to the reduction in size but also because of the influence on their properties due to quantum confinement. These nanostructures can be configured in different ways, highlighting those of the core-shell type.
In this work, we present the results obtained the green synthesis of Ag@Pd bimetallic nanoparticl... more In this work, we present the results obtained the green synthesis of Ag@Pd bimetallic nanoparticles using an aqueous extract of Schinus Molle L. as a reducing and stabilizing agent. The biosynthesis was carried out in two steps; first, seeds of Ag nanoparticles varying the ratio of plant extract/AgNO3-precursor salt were obtained. Second, different K2PdCl4 precursor salt concentration was added to form a palladium shell in the Ag seeds, with no more plant extract addition. The characterization of the nanoparticles was carried out by UV-vis spectroscopy (UV-vis), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). From the UV-vis spectra, it was noted that the typical AgNPs absorption band depressed with the addition of the K2PdCl4 precursor that indicates the Ag@PdNPs formation. The XRD analysis revealed that the as-synthesized Ag@PdNPs have a face-centered cubic structure, SEM and TEM observations showed that most of the obtained...
Journal of Minerals and Materials Characterization and Engineering, 2014
This paper presents the results of the characterization by thermogravimetric analysis of a new co... more This paper presents the results of the characterization by thermogravimetric analysis of a new composite material called polymeric concrete. The polymeric concrete contains micro-particles obtained from High Density Poly-Ethylene (HDPE) mechanically recycled (post-consumer bottles); the official Mexican standard NMX-E-232-SCFI-1999 considers the HDPE as the recyclable plastic material. Thermo-grams based on weight lost were obtained from the raw material (HDPE) and the polymer concrete in order to obtain the glass transition temperature (T g) and melting temperature (T f). The analysis conditions were defined from 20˚C to 180˚C and the heat rate of 1˚C/minute. The results show that the glass transition temperature of polymeric concrete is 46˚C and the HDPE is 38˚C. These results mean that the polymeric concrete is more resistant to decomposition. With respect to the melting temperature, the results show that the 2˚C difference between polymeric concrete and HDPE is not significant. The polymeric concrete with HDPE recycled can be considered as composite material thermoplastic. The new material melts when it is heated to 146˚C and has the ability to be softened, processed and reprocessed with temperature and pressure changes, which make it possible to obtain molded pieces in the desired shape.
Ciencia Nicolaita
El desarrollo científico de los materiales ha estado a la vanguardia del desarrollo tecnológico e... more El desarrollo científico de los materiales ha estado a la vanguardia del desarrollo tecnológico en muchos campos de la ciencia, como la electrónica, la catálisis, el medio ambiente y ahora la medicina, entre otros. Durante el conocimiento básico de los materiales aparecen nuevas propiedades, conceptos y leyes que los rigen, encontrando prácticamente nuevas opciones para cualquier aplicación del desarrollo actual. Los nanomateriales abren una auténtica brecha en este campo debido a la gran diferencia de sus dimensiones con respecto a los micromateriales, acercándonos al control y manipulación de los átomos en el sólido, lo que sin duda permite ajustar sus propiedades y aplicaciones. Este artículo trata sobre algunas diferencias en las propiedades existentes entre la microtecnología representada por los micromateriales y la nanotecnología impulsada por los nanomateriales.
In the present study, gold nanoparticles were synthesized through the Taraxacum officinale plant ... more In the present study, gold nanoparticles were synthesized through the Taraxacum officinale plant extract as a reducing and stabilizing agent. Tetrachloroauric acid was used as the precursor salt. The experimental results were characterized by Ultraviolet-Visible Spectroscopy (UV-Vis), Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). The antioxidant potential (DPPH) of the Taraxacum officinale plant extract was analyzed showing a value of 89.6% that indicates be an excellent reducing agent for synthesizing metal nanoparticles. The presence of the AuNPs was initially confirmed by UV-Vis technique that shows the characteristic SPR absorption band in the range of 500-600 nm. It was found that as the plant extract concentration increases the number of gold nanoparticles formed increased. On the other hand, the FTIR technique showed alcohol, alkanes, aromatics, carboxylic acid, and halides functionals gro...
Materials Letters, 2001
In the present investigation, different alloy compositions close to the ternary composition value... more In the present investigation, different alloy compositions close to the ternary composition values, where the icosahedral phase in AlFeCu is obtained, have been studied. The specimens were obtained using a rapid solidification technique with subsequent thermal treatments of 600°C, 700°C, 800°C and 900°C. The obtained specimens were characterized with X-ray diffraction patterns (XRD) and transmission electron microscopy (TEM). The experimental
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Papers by Gerardo Antonio Rosas Trejo