A Facile Molecular Precursor-based Synthesis of Ag2 Se Nanoparticles and Its Composites with TiO2 for Enhanced Photocatalytic Activity.

The reactions of different silver(I) reagents AgX (X(-) =iodide, trifluoroacetate, triflate) with selenoethers R2 Se (R=Me, tBu) in a variety of solvents were investigated in relation with their use as precursors for Ag2 Se nanomaterials. Different reaction conditions led to different reactivities and afforded either molecular complexes or metal selenide nanoparticles. The reactions leading to in situ formation of the metal selenide nanoparticles were then extended in the presence of commercial TiO2 (P25) to prepare silver selenide-titania nanocomposites with different Ag/Ti ratios. These nanocomposites, well characterized by elemental analysis (Ag, Se), PXRD, TEM, BET, XPS and UV/Vis studies, were investigated as photocatalysts for the degradation of formic acid (FA) solution. The xAg2 Se-TiO2 nanocomposites (x=0.01, 0.13 and 0.25 mol %) exhibited a much higher catalytic activity as compared to P25, which is an established benchmark for the photocatalysis under UV light, and retained a good photocatalytic stability after recycling for several times.