Radiolytic synthesis of Au-Cu bimetallic nanoparticles supported on TiO2: application in photocatalysis

Modification of TiO2 (P25) with Au-Cu bimetallic nanoparticles (NPs) was successfully achieved via a deposition-precipitation method with urea (DPU) followed by radiolytic reduction. This deposition procedure ensures the complete adsorption of Au and Cu ions onto TiO2. Small Au-Cu NPs homogeneous in size were obtained. The alloyed structure of Au-Cu NPs was confirmed by HAADF-STEM, EDS, HRTEM and XPS techniques. The photocatalytic properties of the modified TiO2 have been studied for photodegradation of methyl orange. The modification with Au-Cu bimetallic nanoparticles induces an enhancement in the photocatalytic activity under UV irradiation. The highest photocatalytic activity was obtained with Au-Cu/TiO2 (Au/Cu = 1:3). Bimetallic Au-Cu NPs act as efficient electron scavengers increasing the photocatalytic activity under UV light.