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

Abstract

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.