Noble Metal Promoted TiO2 from Silver-Waste Valorisation: Synergism between Ag and Au

Wastewaters from precious metal industries contain high amounts of noble metals, but their efficient recycling is hindered by the wastewater complex composition. Here, we propose an innovative approach for recovery metals contained in these metal-enriched wastewaters as precursors synthesis nanoparticles (NPs) and supported catalysts. Silver NPs were synthesized Ag-enriched then deposited on TiO2 to prepare photocatalysts. Then, further promotion photocatalytic activity Ag-modified was achieved addition little 0.5 wt.% Au. STEM-EDS analyses proved that Au located Ag or AgOx nanoparticles. The contact between two metal-containing results charge transfer effects, appreciable both terms oxidation states determined XPS optical properties. In particular, plasmon band shows photochromic effects: under UV light irradiation, bimetallic samples exhibit a blue-shift band, which reversible dark storage. materials tested towards ethanol photodegradation light. Adding resulted promoted compared Ag-TiO2, thus showing synergistic effects Ag. Ethanol completely converted already after 1 h acetaldehyde formed main product fully degraded less than 180 min. Notably, showed ethylene formation parallel dehydration mechanism.