Fotokatalytická produkce vodíku v přítomnosti fotokatalyzátorů NiO/TiO2 z vodného roztoku methanolu

Abstract

This bachelor thesis deals with photocatalytic hydrogen production in the presence of NiO/TiO2 photocatalysts in aqueous methanol solution. The photocatalysts were prepared by two-step calcination and then characterized by available techniques. The photocatalytic reaction was carried out in a stainless-steel batch photoreactor under illumination of an 8 W Hg UV lamp (λ = 254 nm). Gas samples were taken at hourly intervals (0-3 h) and analyzed on a gas chromatograph with a BID detector. All NiO/TiO2 photocatalysts showed higher photoactivity than the pure TiO2 photocatalyst. This enhanced photoactivity is related to the higher specific surface area of the NiO/TiO2 composites compared to pure TiO2, but mainly to the improved electron-hole separation that occurred due to the formation of p-n heterojunctions between NiO and TiO2. The highest hydrogen yields were achieved in the presence of the 0,1-NiO/TiO2 composite, which was 1,3 times higher than the hydrogen yields in the presence of the TiO2 photocatalyst after three hours of irradiation.