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Metallic nanoparticles-modified by in situ real-time TEM and femtosecond pulsed laser and incorporated into chitosan

Grant number: 17/13008-0
Support type:Scholarships abroad - Research Internship - Post-doctor
Effective date (Start): September 04, 2017
Effective date (End): August 31, 2018
Field of knowledge:Physical Sciences and Mathematics - Chemistry - Inorganic Chemistry
Principal Investigator:Elson Longo da Silva
Grantee:Paula Fabiana dos Santos Pereira Lima
Supervisor abroad: Juan Manoel Andres Bort
Home Institution: Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil
Local de pesquisa : Universitat Jaume I, Spain  
Associated to the scholarship:14/14171-4 - Investigation of the crystalline structure and photoluminescence, photocatalytic and antibacterial properties of the nanocrystals (Ag2-2xZnX)WO4 with (x = 0, 0.25, 0.50, 0.75 and 1) incorporated in chitosan, BP.PD


Metal nanoparticles composed of one or more elements are attracting interest due to the antibacterial, catalytic, optical, electronic, thermal, tribological properties, as in the case of the Ag, Zn and Cu composites. Biopolymers constitute important sources of novel functional materials and advantageous alternatives to synthetic polymers in biomedical applications. Thus, the synthesis of metal-chitosan composites is attracting increasing scientific interest due to their fascinating applications in catalysis, sensors and biomaterials. The capability of chitosan as a chelating agent makes it a perfect material for metal nanoparticle synthesis. However, innovative synthesis methodologies that make possible their formations with shape, size and controlled dispersions being an effective techinique for changing or modifying materials and is a suitable tool for the creation of new materials for future applications. Some examples include materials that can be used as photocatalysts for water splitting reaction for hydrogen production from breakdown of H2O molecules and photo-degradation of organic dyes in wastewater as well as for photoanodes in dye-sensitized solar cells and light absorbers. Understanding the growth processes as well as handling them during the synthesis process allows the controlled of such materials. In this sense, the synthesis by electron beam irradiation in a Transmission Electron Microscope (TEM) becomes a powerful methodology for the preparation of nanostructures, since it allows to carry out in situ studies of nanoparticles growth phenomena. On the other hand, treatments with femtosecond laser also allow the formation of nanostructures induced by laser irradiation. Thus, the present research project has the proposal of obtaining metallic nanoparticles composed of Ag, Zn and Cu by electron beam irradiation in the TEM and by Femtosecond laser methods, using ±-Ag2-2xMxWO4 (M = Zn, Cu) microcrystals, as precursor sources, and then, obtain chitosan films incorporated with irradiated and non-irradiated nanoparticles. Other objective in this project is to obtain and study Ag, Zn and Cu-chitosan irradiated by Femtosecond laser in liquid. It is also the objective of this project to propose mechanisms of growth of the metallic nanoparticles by in situ real-time in TEM. The materials in this work will also be evaluated and characterized by X-ray diffraction, absorption spectroscopy in the Fourier transform infrared region, Micro-Raman spectroscopy, X-ray excited photoelectron spectroscopy, field emission scanning electron microscopy, selected area electron diffraction, and X-ray dispersive energy spectroscopy.

Scientific publications
(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)
LAIER, LETICIA O.; ASSIS, MARCELO; FOGGI, CAMILA C.; GOUVEIA, AMANDA F.; VERGANI, CARLOS E.; SANTANA, LUIS C. L.; CAVALCANTE, LAECIO S.; ANDRES, JUAN; LONGO, ELSON. Surface-dependent properties of alpha-Ag2WO4: a joint experimental and theoretical investigation. THEORETICAL CHEMISTRY ACCOUNTS, v. 139, n. 7 JUN 10 2020. Web of Science Citations: 0.
PEREIRA, P. F. S.; GOUVEIA, A. F.; ASSIS, M.; DE OLIVEIRA, R. C.; PINATTI, I. M.; PENHA, M.; GONCALVES, R. F.; GRACIA, L.; ANDRES, J.; LONGO, E. ZnWO4 nanocrystals: synthesis, morphology, photoluminescence and photocatalytic properties. Physical Chemistry Chemical Physics, v. 20, n. 3, p. 1923-1937, JAN 21 2018. Web of Science Citations: 26.

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