Photodeposition of Ag and Cu binary co-catalyst onto TiO2 for improved optical and photocatalytic degradation properties

This paper deals with the influence of binary co-deposition of Ag and Cu metals on TiO₂ photocatalyst to investigate its adsorption, optical and photocatalytic properties relative to monometallic (Ag/Cu) deposition. Hence, different proportion of Ag and Cu has been simultaneously deposited on TiO₂ in an inert (argon) atmosphere under UV irradiations. It was found that the plasmonic absorption bands appeared in the visible region (480 and 640?nm for Ag and Cu, respectively) due to the binary deposition of Ag-Cu nanoparticles (～9–20?nm) onto TiO₂ surface as revealed by TEM size analysis and EDS/elemental mapping. The fluorescence spectrum of Ag-Cu-TiO₂ showed higher quenching of emission peak intensities at λ?>?450?nm in a different extent due to efficient charge separation as compared to respective monometallic (Ag/Cu)-TiO₂ nanocomposites. The photocatalytic activities of binary Ag-Cu-TiO₂ for the degradation of methylene blue and salicylic acid under UV and visible irradiations were found to be notably higher than monometallic deposited TiO₂. The reaction rates and CO₂ formation exhibited due to binary deposition always gives enhanced photoactivity which could be useful for removal of toxic environmental pollutants under solar radiations.