Ag-decorated TiO2 nanostructured materials are promising photocatalysts. We used non-standard cryo-lyophilization and ArF laser ablation methods to produce TiO2 nanosheets and TiO2 nanostructured thin films decorated with Ag nanoparticles. Both methods have a common advantage in that they provide a single multiply twinned Ag(0) characterized by {111} twin boundaries. Advanced microscopy techniques and electron diffraction patterns revealed the formation of multiply twinned Ag(0) structures at elevated temperatures (500 °C and 800 °C). The photocatalytic activity was demonstrated by the efficient degradation of 4-chlorophenol and Total Organic Carbon removal using Ag-TiO2 nanosheets, because the multiply twinned Ag(0) served as an immobilized photocatalytically active center. Ag-TiO2 nanostructured thin films decorated with multiply twinned Ag(0) achieved improved photoelectrochemical water splitting due to the additional induction of a plasmonic effect. The photocatalytic properties of TiO2 nanosheets and TiO2 nanostructured thin films were correlated with the presence of defect-twinned structures formed from Ag(0) nanoparticles with a narrow size distribution, tuned to between 10 and 20 nm. This work opens up new possibilities for understanding the defects generated in Ag-TiO2 nanostructured materials and paves the way for connecting their morphology with their photocatalytic activity.

Department of Physics Norwegian University of Science and Technology NO 7491 Trondheim Norway

Faculty of Mechanical Engineering JE Purkyně University Pasteurova 1 400 96 Ústí nad Labem Czech Republic

Institute of Chemical Process and Fundamentals of the Czech Academy of Sciences Rozvojova 2 135 165 02 Prague Czech Republic

Institute of Inorganic Chemistry of the Czech Academy of Sciences 250 68 Husinec Rez Czech Republic

Institute of mineralogy and crystallography Bulgarian Academy of Sciences 107 Acad G Bonchev Str 1113 Sofia Bulgaria

Institute of Physics of the Czech Academy of Sciences Na Slovance 1999 2 182 21 Prague Czech Republic

J Heyrovsky Institute of Physical Chemistry of the Czech Academy of Sciences Dolejskova 2155 3 182 23 Prague Czech Republic

Nuclear Physics Institute of Czech Academy of Sciences 250 68 Husinec Rez Czech Republic

STU Centre for Nanodiagnostics University Science Park Bratislava Centre Slovak University of Technology Vazovova 5 811 07 Bratislava Slovakia

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