Browsing by Author "Granbohm, Henrika"

Plasmonic photocatalysts are emerging as a new group of photocatalysts with both UV and visible light activation, and show promising uses in wastewater treatment, water splitting and CO2 reduction by using sunlight. Plasmonic photocatalysts consist of noble metal nanoparticles dispersed onto a semiconductor photocatalyst and have two outstanding features: a Schottky junction and localised surface plasmonic resonance. By tailoring the size and shape of the noble metals and carefully choosing the right structure and composition of the photocatalyst material, it is possible to achieve enhanced photocatalytic efficiency and response to visible light. The aim of the experimental part in this work was to synthesise inorganic composite powders of GO/TiO2/Ag/AgCl and GO/SiO2/Ag/AgCl (GO, graphene oxide) and investigate their photocatalytic properties. Different synthesis parameters were modified during preparation of the composites. The loading of GO in GO/SiO2/Ag/AgCl composite and the reduction of silver ions by polyvinylpyrrolidone (PVP) in the synthesis of GO/TiO2/Ag/AgCl were examined. The photocatalytic activity was investigated by degradation of methylene blue (MB) for all composite powders and compared to a reference material (TiO2, Degussa P25). Thin films of selected GO/SiO2/Ag/AgCl compositions were prepared by dip coating. The photocatalytic measurements showed that the MB degradation rate of GO/SiO2/Ag/AgCl with 50 wt.% GO loading was comparable to Degussa P25. GO/TiO2/Ag/AgCl composites prepared using 2.5 ml and 0 ml of PVP during preparation showed superior MB degradation rates compared to Degussa P25. Preliminary depositions of GO/SiO2/Ag/AgCl thin films on glass substrates were rough, with a thickness up to 600 nm. Further research is required for thin film deposition on Si-substrates.