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Novos nanocompósitos de óxido de titânio para a produção de hidrogénio solar
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Advisor(s)
Abstract(s)
RESUMO: Neste trabalho foram sintetizados uma série de novos compósitos de TiO2-rGO e TiO2-g-C3N4, como base para o desenvolvimento de fotocatalisadores ativos na produção de hidrogénio solar a partir de soluções aquosas de etanol. Os compósitos foram dopados com metais nobres e de transição (Pt, Au e Cu), tendo sido estes fotodepositados a partir dos respetivos sais. Para 6 h de irradiação UV, o volume de gás produzido com os catalisadores TiO2-Pt1.5% e TiO2-Au1.5% é semelhante, embora com perfis de velocidade diferentes, que mostram 2 declives no caso da Pt. A substituição da Pt por Cu deu resultados promissores em termos de gás produzido, ainda que nas presentes condições experimentais não foi significativamente alterado pela presença de rGO ou g-C3N4. A irradiação contínua até 24 h evidenciou velocidades constantes para os fotocatalisadores TiO2-Cu contrariamente ao TiO2-rGO3%-Pt3.8% cuja produção de gás parou pelas 12 h, devido a envenenamento pelos produtos de oxidação do etanol. A substituição de Pt por Cu revela-se também vantajosa considerando as questões associadas à escassez e custo da Pt.
ABSTRACT: In this work, a new series of composite materials based on TiO2-rGO e TiO2-g-C3N4 were synthesized in the search for active photocatalysts for solar hydrogen production in aqueous ethanol containing solutions. The composites were doped with noble and transition metals (Pt, Au e Cu), which were photodeposited from solutions of their respective salts. Using UV irradiation up to 6 h, photocatalyst TiO2-Pt1.5% and TiO2-Au1.5%, produced similar amounts of gas but their production rate profiles were different, with a 2 slope profile in the case of Pt. The substitution of Pt by Cu gave promising results in terms of volume of gas produced, which in the present experimental conditions was not significantly influenced by the presence of rGO or g-C3N4. Continuous irradiation up to 24 h evidenced constant hydrogen production rates for TiO2-Cu photocatalysts over the whole testing period, contrary to TiO2-Pt composites that stopped producing hydrogen after 12 h, due to active site poisoning by ethanol oxidation products. Pt substitution by Cu is also advantageous in tackling the associated Pt scarcity and cost issues.
ABSTRACT: In this work, a new series of composite materials based on TiO2-rGO e TiO2-g-C3N4 were synthesized in the search for active photocatalysts for solar hydrogen production in aqueous ethanol containing solutions. The composites were doped with noble and transition metals (Pt, Au e Cu), which were photodeposited from solutions of their respective salts. Using UV irradiation up to 6 h, photocatalyst TiO2-Pt1.5% and TiO2-Au1.5%, produced similar amounts of gas but their production rate profiles were different, with a 2 slope profile in the case of Pt. The substitution of Pt by Cu gave promising results in terms of volume of gas produced, which in the present experimental conditions was not significantly influenced by the presence of rGO or g-C3N4. Continuous irradiation up to 24 h evidenced constant hydrogen production rates for TiO2-Cu photocatalysts over the whole testing period, contrary to TiO2-Pt composites that stopped producing hydrogen after 12 h, due to active site poisoning by ethanol oxidation products. Pt substitution by Cu is also advantageous in tackling the associated Pt scarcity and cost issues.
Description
CIES2020 - XVII Congresso Ibérico e XIII Congresso Ibero-americano de Energia Solar
Keywords
Solar hydrogen Photocatalytic Titanium dioxide Carbon nitride Wastewater treatment Clean energy
Pedagogical Context
Citation
Capelo, A... [et.al.] - Novos nanocompósitos de óxido de titânio para a produção de hidrogénio solar. In: CIES2020: As Energias Renováveis na Transição Energética: Livro de Comunicações do XVII Congresso Ibérico e XIII Congresso Ibero-americano de Energia Solar. Helder Gonçalves, Manuel Romero (Ed.). Lisboa, Portugal: LNEG, 3-5 Novembro, 2020, p. 823-831
Publisher
LNEG - Laboratório Nacional de Energia e Geologia