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

Abstract

Bilayer Au-TiO2 configuration with two-dimensional (2D) TiO2 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 35nm thick 2D TiO2 film was developed by atomic layer deposition (ALD) on Si/SiO2-Au substrate. The Au-TiO2 bilayer demonstrated the improved photocatalytic and photovoltaic performances compared with those TiO2 films developed on Si/SiO2 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-TiO2 interface which contributed to the electron injection to conduction band of TiO2 or facilitated the separation of generated electron-hole pairs at Au-TiO2 Schottky junction.