Au–NiOx nanocomposite for hot electron-assisted plasmonic photocatalysis

Abstract

Nanocomposites of metal–oxide semiconductors containing Au nanoparticles are emerging multifunctional materials for sunlight-driven highly efficient photocatalysis. Here we report a solution-processed nanocomposite synthesis of Au–NiO_x nanocomposite films by slot-die coating and plotter printing in a straightforward in situ synthesis approach. Our study demonstrated a significantly enhanced photocatalytic decomposition reaction of MO upon exposure of Au–NiO_x films to a sunlight simulator. The excellent photocatalytic activity is ascribed to the generation of hot carriers after LSPR excitation in Au NPs. Suitable band alignment between the valence band of NiO_x and the Fermi level of Au NPs leads to the efficient extraction of the corresponding hot holes by the NiO_x layer. This results in longer lifetime of the generated hot electrons to drive the photodegradation of methyl orange by generating reactive oxygen species (ROS). We found by free radical capture experiments that ˙O₂⁻ was the major ROS in the photocatalytic reaction.