The surface of commercial TiO2 compounds (P25 and ST01) has been modified with Ag nanopartides induced by radiolysis. On P25, the Ag nanoclusters are very small (1—2 nm) and homogeneous in size while on ST01, two populations of nanopartides are obtained, small nanopartides (1—2 nm) and larger ones (mean diameter 7 to 12 nm depending on the silver loading). The photocatalytic properties of Ag-modified TiO2 have been studied for phenol photodegradation in aqueous suspensions under UV and visible light. Their electronic properties have been studied by time resolved microwave conductivity (TRMC) to follow the charge-carrier dynamics. TRMC measurements show that the TiO2 modification (P25 and ST01) with Ag nanopartides plays a role in charge-carrier separations increasing the activity under UV light. Indeed, Ag nanopartides act as electron scavengers, decreasing the charge carrier recombination. TRMC measurements show also that more electrons are produced in the conduction band of P25 under UV illumination of Ag-modified P25. Surface modification by silver nanopartides induces also a modification of the absorption properties of the photocatalyst creating an activity under visible fight.
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