Obtenção de hexaniobatos lamelares modificados com nanopartículas de ouro para a produção fotocatalítica de hidrogênio

Abstract

The growing demand for energy resources, combined with concerns about global warming, requires the improvement and development of new technologies based on renewable energy sources. In this scenario, potassium hexaniobate, K4Nb6O17, has great potential for applications in energy and also environmental issues by acting as a photocatalyst to promote chemical reactions of interest in these areas. In this work, the modification of lamellar hexaniobate with gold nanoparticles modified with polyethyleneimine (PEI) was evaluated in different proportions: 0.50%, 0.75%, 1.00% and 2.00% w/w. The composite was used as a photocatalyst for H2 evolution from aqueous methanol solutions. The Au nanoparticles employed have positive surface charges over a wide pH range, thus facilitating intercalation between the negatively charged lamellae of the niobates. The strong interaction between niobate and nanoparticles encapsulated with PEI definitely plays an important role in photocatalytic performance as they guarantee the electronic interaction between the two materials. After the insertion of 2% gold nanoparticles in the exfoliated niobate, the increase in H2 production is promising, the material produced almost 8 times the amount of H2 produced by the exfoliated niobate, resulting in a production speed of 1.8 x 10-4 mol h-1g-1.