Síntese e caracterização de catalisadores a base de nióbio dopados com carbono por fotocatálise

Abstract

In this work, the Nb2O5 catalysts were doped with carbon and tested in hydrogen evolution and Rhodamine 6G degradation, using renewable and low-cost sources as follows: sugarcane bagasse, sodium alginate and sucrose. Hydrothermal and mechanical incorporation with subsequent heat treatment methods were used to prepare the photocatalysts. The catalysts were characterized by several techniques such as ultraviolet-visible spectroscopy (UV-vis), X-ray diffraction (XRD), elementary analysis (CHN), Fourier-transform infrared spectroscopy (FT-IR), N2 adsorption (ASAP), scanning electron spectroscopy (SEM) and thermogravimetry (TGA). The hydrogen evolution tests were made using a photocatalytic cell developed in our laboratory and a solar simulator as an irradiation source; the quantification of hydrogen was analysed by TCD-GC (gas chromatography with thermal conductivity detector). Regarding Rhodamine degradation, it was analysed by ultraviolet-visible spectroscopy (UV-vis). The carbon-doped Nb2O5 with sugarcane bagasse as its carbon source, named NbOx BC 1:4 4 600C Pt, exhibited enhanced photocatalytic activity toward hydrogen evolution (172,0 mol cm-2) under visible light in 20 minutes of irradiation, showing this catalyst to be a strong candidate for photocatalyst green hydrogen evolution. The carbon-doped Nb2O5 with sucrose as its carbon source exhibited a 90% degradation of rhodamine 6G after 60 minutes under blue LED irradiation. The catalysts prepared using sodium alginate as their carbon source did not demonstrate any photocatalytic activity either for hydrogen production or for rhodamine 6G degradation.