Titanium and zirconium-based mixed oxides prepared by using pressurized and supercritical fluids: On novel preparation, microstructure and photocatalytic properties in the photocatalytic reduction of CO2

• Published in: Catalysis today 2017-06, Vol.287, p.52-58
• Main Authors: Kočí, K., Matějová, L., Troppová, I., Edelmannová, M., Prostějovský, T., Peikertová, P., Brunátová, T., Lang, J., Čapek, L., Obalová, L.
• Format: Article
• Language: English
• Subjects: Carbon dioxide; Microstructure; Photocatalysis; Pressurized fluid; Supercritical fluid; ZrxTi1-xOn mixed oxides
• ISSN: 0920-5861; 1873-4308
• DOI: 10.1016/j.cattod.2016.11.052

[Display omitted] •Novel preparation of ZrxTi1-xOn mixed oxides by processing using pressurized hot water and supercritical methanol.•ZrxTi1-xOn mixed oxides investigated in the CO2 photocatalytic reduction.•TiO2 anatase-brookite mixture (67:33wt.%) resulted in the highest photoactivity.•Optimal Ti:Zr molar ratio of 0.9:0.1 in the ZrxTi1-xOn mixed oxide.•Small anatase and brookite crystallite-size allowed optimal optical and electronic properties. The ZrxTi1-xOn mixed oxides with various Ti:Zr molar ratios and parent TiO2 and ZrO2 were prepared unconventionally, combining the reverse micelles-controlled sol-gel method with high-pressure processing by pressurized and supercritical fluids. The mixed oxides were characterized using several complementary characterization methods and investigated in the photocatalytic reduction of CO2. Applied novel unconventional processing affected significantly the (micro)structure of mixed oxides, which was further reflected to their optical and thus electronic properties. The Zr0.1Ti0.9On mixed oxide showed the best photocatalytic behavior in a consequence of the optimal crystallinity and the lowest band gap energy from all mixed oxides. The Zr0.1Ti0.9On mixed oxide was of bicrystalline TiO2 anatase-brookite structure (67:33wt.%) showing small crystallite-sizes, which allowed the optimal surface phase junction.