Ovcharov M. Photocatalytic reduction of carbon dioxide on metal (Cu, Au, Ag)-containing nanostructures based on TiO2 and C3N4

The thesis deals with the relationships between the photocatalytic activity of nanostructured semiconductor materials based on TiO2 and C3N4 and its morphology in CO2 reduction photoprocesses. The highest photoactivity was achieved by irradiation of mesoporous TiO2-materials as well as TiO2 microspheres. It is shown that the highest anodic photoactivity among explored Ti/TiO2 electrodes characteristically for anodes based on TiO2 nanotubes.It was established that the porous C3N4 samples obtained by matrix synthesis exhibit high activity during CO2 photoreduction to acetaldehyde. It is shown that the deposition of metal nanoparticles on the TiO2 surface leads to increase of CO2 photoreduction velocity, the highest photoactivity inherent for TiO2/Cu composite due to catalytic properties of copper, wherein deposition of Cu nanoparticles on porous carbon nitride leads to slowing down of acetaldehyde formation. For the first time it was shown that the bimetallic nanocomposites TiO2/Au/Cu and TiO2/Ag/Cu, compared to monometallic TiO2/Au, TiO2/Ag and TiO2/Cu, exhibit much higher activity during CO2 photoreduction, the rate of CH4 formation significantly depends on the order of precipitation of metals - the highest photoactivity is inherent for composites obtained by initial deposition of noble metal nanoparticles, followed by deposition of a layer of catalytically active copper on them.