Au@ZnO nanostructures on porous silicon for photocatalysis and gas-sensing: the effect of plasmonic hot-electrons driven by visible-light

Nanostructured heterojunctions play key role for transfer and separation of interfacial photo-carriers. At visible light illumination, the effects of Au nanoparticles (NPs) for the photocatalysis and gas-sensing performance of Au@ZnO nanstructures on porous silicon layer are reported. At optimized loading amount of Au NPs, the local surface plasmon resonance (LSPR) effect of Au NPs is studied. Generated by visible light irradiation, the LSPR effect of Au NPs promotes desorption and activation of surface adsorption oxygen species -O-2(-), which is initiated by hot electrons transfer through Au-ZnO nanojunctions. This mechanism is responsible for the enhanced photocatalysis of methyl orange molecular, as well as enhancing the detecting performance for ammonia (NH3) gas at room temperature.