Banca de QUALIFICAÇÃO: ADRIANA SOARES DE CARVALHO

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : ADRIANA SOARES DE CARVALHO
DATE: 03/11/2023
LOCAL: Programa de Pós-Graduação em Ciência de Materiais
TITLE:

Production of Hybrid Nanocomposites Based on Nitrogen-Doped Graphene Aerogel and Metal Oxide Nanoparticles (CoxFeyOz@NrGO) and their Applications

KEY WORDS:

graphene, aerogel, magnetite, ferrite, electromagnetic shielding, supercapacitors.

PAGES: 35
BIG AREA: Outra
AREA: Multidisciplinar
SUMMARY:

In this study, hybrid nanocomposites (CoxFeyOz@NrGO) based on metal oxide nanoparticles and nitrogen-doped reduced graphene oxide aerogel (NrGO) were synthesized through ex-situ, simple and easily scalable approaches. NrGO exhibited 7.96 at% N, demonstrating efficient doping and high content of active nitrogen sites of the aerogel matrix. The characteristic bands of C-N/C=N bonds were identified, with a high N/O ratio of 1.37. The NrGO conductive matrix had only 5 layers, indicating excellent quality, and mesoporous morphology with high interconnection of pores that reflected a surface area of 995.6 m2/g. From NrGO, it was possible to produce Fe3O4@NrGO using the direct mixing method. This methodology made it possible to obtain a matrix with a good distribution of Fe3O4 (magnetite) nanoparticles and explore the interesting swelling mechanism, which resulted in a significant increase in surface area, reaching 1456.0 m2/g. This Fe3O4@NrGO nanocomposite was investigated for applications in the area of electromagnetic pollution shielding (EMI SE), obtaining an average of 15.9 dB in the X-band range for ultra-thin and light free-binder pellets. The values normalized by thickness and mass were higher than those reported in the literature. The advantages of Fe3O4@NrGO wafers were also investigated for applications in energy storage systems, specifically in supercapacitors, indicating good prospects in the current scenario. Other nanocomposites based on Fe2O3 (hematite) and CoFe2O4 (cobalt ferrite) nanoparticles were also synthesized using different methods, obtaining structures with notable morphologies with expected applications in both the areas mentioned and in catalysis, sensors, among others.

COMMITTEE MEMBERS:
Externa ao Programa - 2053365 - JULIANA ANGEIRAS BATISTA DA SILVA - nullExterno à Instituição - YURIMILER LEYET RUIZ - UFAM