Banca de DEFESA: MARIA DEL ROSARIO DIAZGRANADOS JIMENEZ

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : MARIA DEL ROSARIO DIAZGRANADOS JIMENEZ
DATE: 05/02/2024
TIME: 14:00
LOCAL: On-line
TITLE:

Graphitic Carbon Nitride doped with Sulfur: Preparation, Experimental and Theoretical Characterization

KEY WORDS:

g-C₃N_4, Nanosheets, Sulfur Doping, DFT.

PAGES: 72
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Química Inorgânica
SPECIALTY: Físico Química Inorgânica
SUMMARY:

The growing global concern regarding the presence of dyes in wastewater and water resources is noteworthy because of their resistance, toxicity, and carcinogenic potential, which affect aquatic life and human health. Effective removal of these substances before disposal into the environment is crucial. In this study, graphitic carbon nitride (g-C₃N₄) photocatalysts were prepared to degrade methylene blue with and without sulfur doping. Five samples with different doping ratios were produced using urea and thiourea as precursors in the proportions of 100:0, 70:30, 50:50, 30:70, and 0:100%, respectively. This method allowed the cost-effective synthesis of materials through a simple two-step process: precursor pyrolysis followed by liquid-phase exfoliation via ultrasonication to produce nanosheets. The photocatalysts were characterized using experimental methods (UV-vis, PL, lifetime, PLQY, XRD, and FT-IR) and theoretical studies employing density functional theory (DFT). The results reveal that among the doped samples, T50U50 shows remarkable improvements, including an extended lifetime, increased quantum yield, reduced bandgap, efficient charge transfer, and notable degradation efficiency of up to 97% in 150 min, accompanied by a substantially faster reaction rate. Sulfur doping demonstrates its capability to provide electrons to the electronic structure, contributing to bandgap reduction and inducing the inclusion of additional electrons and spin polarization.

BANKING MEMBERS:
Externo ao Programa - 2543097 - CLAUDIO DE OLIVEIRA
Externo à Instituição - HELIO ANDERSON DUARTE
Interno - 1443844 - MARCO ANTONIO SCHIAVON
Externa ao Programa - 1954071 - MARIA CRISTINA SILVA