Pontos quânticos de grafeno dopado/TiO2 nanoparticulado: síntese e caracterização de têxteis fotoluminescentes multifuncionais

Abstract

Nitrogen-Doped Graphene Quantum Dots (N-GQDs) and TiO2 nanoparticles were applied on textile fibers to obtain new multifunctional materials with UV protection, self-cleaning and photoluminescence properties. The N-GQDs were synthesized by means of citric acid and urea pyrolysis. The TiO2 nanoparticles were synthesized via sol-gel process using titanium isopropoxide as a precursor. Cotton fabrics were coated with the nanoparticles in a hydrothermal process using polyvinyl alcohol (PVA) as a binding agent. The N-GQDs were characterized by Fourier Transform Infrared (FTIR), High Resolution Transmission Electron Microscopy (HRTEM), X-ray Diffracion (XRD), UV-vis and photoluminescence spectroscopy. TiO2 was characterized by HRTEM and XRD. The nano-coated fabrics were characterized by diffuse reflectance spectroscopy, Field Emission Scanning Electron Microscopy (FESEM), UV-vis spectroscopy, X-ray Excited Photoelectron Spectroscopy (XPS), Atomic Force Microscopy (AFM) and XRD. Self-cleaning activity was assessed by measures of intensity of discoloration of cationic dye in the functionalized fabrics. An association between N-GQDs and TiO2 resulted in an efficiency of 91.1% in the presence of UV light in the photocatalysis of the dye. UV protection was assessed using an Australian standard and it was observed that both N-GQDs and TiO2 nanocoated fabrics as well as N-GQDs / TiO2 resulted in a level of protection classified as excellent. Thus, a new hybrid textile material was obtained.