Wafer-scale two-dimensional Au-TiO2 bilayer films for photocatalytic degradation of Palmitic acid under UV and visible light illumination

Abstract Bilayer Au-TiO 2 configuration with two-dimensional (2D) TiO 2 films enabled sensible improvement in photocatalytic degradation of Palmitic Acid (PA) and also the enhancement of current density under visible light illumination. The improved visible light photocatalytic and photocurrent properties were attained when 35 nm thick 2D TiO 2 film was developed by atomic layer deposition (ALD) on Si/SiO 2 -Au substrate. The Au-TiO 2 bilayer demonstrated the improved photocatalytic and photovoltaic performances compared with those TiO 2 films developed on Si/SiO 2 bare substrate. These improvements can be attributed to the plasmonic effects of Au film acting as antenna for visible light and also serving as hole acceptor during photocatalysis process. The proposed mechanisms for enhanced visible light performance of bilayer films are hot electron injection and the formation of hot spots at Au-TiO 2 interface which contributed to the electron injection to conduction band of TiO 2 or facilitated the separation of generated electron-hole pairs at Au-TiO 2 Schottky junction.