Estudo fotocatalítico de filmes de nanocristais de TiO2 incorporados com nanobastões de ouro
Technological advances increasingly demand the development of materials with unique and differentiated chemical and physical properties. Such properties can be obtained by the elaboration of a titanium dioxide (TiO2) nanoparticulate system incorporated with gold nanorods (AuNR's). The first bei...
| Autor principal: | Santos, Roberta Caroline dos |
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| Formato: | Trabalho de Conclusão de Curso (Graduação) |
| Idioma: | Português |
| Publicado em: |
Universidade Tecnológica Federal do Paraná
2022
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| Assuntos: | |
| Acesso em linha: |
http://repositorio.utfpr.edu.br/jspui/handle/1/27528 |
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| Resumo: |
Technological advances increasingly demand the development of materials with unique and differentiated chemical and physical properties. Such properties can be obtained by the elaboration of a titanium dioxide (TiO2) nanoparticulate system incorporated with gold nanorods (AuNR's). The first being a highly implemented semiconductor in the field of photocatalysis due to its low cost, and the second, a noble metal used in low concentrations to incorporate the plasmonic resonance effect in the energy system activated via ultraviolet/visible light. In this sense, the present study aimed to synthesize, characterize and analyze the photocatalytic effect of these nanoparticles, when exposed to a reaction medium containing organic molecules of the Rhodamine group. This system showed better photocatalytic performance in dye degradation, with efficiency of up to 97.8% in 90 minutes, when using a higher aspect ratio (AR) AuNR's morphology, showing a strong dependence on the charged AuNR's. The sample incorporated with low aspect ratio nanoparticles, tending to a spherical morphology, did not change its absorption intensity during the proposed time, presenting an efficiency of 2.67%, with only small peak displacements during the process. This may be associated with the fact that this nanomaterial has a short longitudinal length, and with this there are smaller plasmon oscillations on the surface of the gold. The highest degradation efficiencies were presented in the gold nanorods with the highest aspect ratios, at 90 minutes of irradiation, final analysis time. As a comparison, the efficiency results found were increasing TiO2 / 55 μL AuNR's < (TiO2) Isolated < TiO2 / 125 μL AuNR's < TiO2 / 160 <AuNR's. Samples with long longitudinal length gold nanorods performed better than systems using only TiO2, with the difference that they are occurring on the incidence of longer wavelengths (in the visible spectrum). This result shows that a mixture of the two Au/ TiO2 structures can significantly optimize the photocatalytic properties of nanoparticles, and consequently, allow this effect to occur under sunlight. |
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