Preparation, characterization and photocatalytic performance of TiO2 prepared by using pressurized fluids in CO2 reduction and N2O decomposition

Abstract

TiO 2 photocatalyst was prepared unconventionally, using the sol-gel process controlled within the reverse micelles and the processing by pressurized hot fluids as an alternative to standard calcination. Conventional calcined TiO 2 was prepared as well. Textural, microstructural and optical properties of prepared photocatalysts were characterized by using nitrogen physisorption, powder X-ray diffraction and DR UV-Vis spectroscopy. The photocatalytic properties of developed TiO 2 catalysts were investigated in the photocatalytic reduction of CO 2 and photocatalytic decomposition of N 2 O. It was revealed that TiO 2 processed by pressurized hot fluids shows significantly improved textural properties and different crystallinity compared to its calcined analog. Yields of both reaction products (H 2 and CH 4 ) of CO 2 photoreduction were higher for the extracted TiO 2 photocatalyst. The same result was achieved in N 2 O photodecomposition. The maximum N 2 O conversion (83 % after 20 h of illumination) in inert gas was reached also over the TiO 2 extracted photocatalyst, and it can be attributed to simultaneous N 2 O photocatalytic decomposition and N 2 O photolysis. Reaction kinetics of N 2 O-photoinduced decomposition was described well by the pseudo-first-rate law. The surface heterojunction of bicrystalline anatase-brookite phase corresponded to better catalytic activity of TiO 2 processed by pressurized hot fluids in both reactions, in a consequence of reduced electron-hole pair recombination. Graphical Abstract& Kamila Kočí

Photocatalytic Decomposition of N2O by Using Nanostructured Graphitic Carbon Nitride/Zinc Oxide Photocatalysts Immobilized on Foam

“…Catalysts 2019, 9, Photocatalytic decomposition of nitrous oxide was studied on Cu ions embedded on various oxides, e.g., (SiO 2 ·Al 2 O 3 , Al 2 O 3 , SiO 2 ) [2], ZnS [3], TiO 2 [4], TiO 2 doped by Ag [5][6][7], Ce [8,9].…”