Iridium Oxide-Assisted Plasmon-Induced Hot Carriers: Improvement on Kinetics and Thermodynamics of Hot Carriers

Plasmonic nanostructures are capable of driving photocatalysis through absorbing photons in the visible region of the solar spectrum. Unfortunately, the short lifetime of plasmon-induced hot carriers and sluggish surface chemical reactions significantly limit their photocatalytic efficiencies. Moreover, the thermodynamically favored excitation mechanism of plasmonic photocatalytic reactions is unclear. The mechanism of how the plasmonic catalyst could enhance the performance of chemical reaction and the limitation of localized surface plasmon resonance devices is proposed. In addition, a design is demonstrated through co-catalyst decorated plasmonic nanoparticles Au/IrO_X upon a semiconductor nanowire-array TiO₂ electrode that are able to considerably improve the lifetime of plasmon-induced charge-carriers and further facilitate the kinetics of chemical reaction. A thermodynamically favored excitation with improved kinetics of hot carriers is revealed through electrochemical studies and characterization of X-ray absorption spectrum. This discovery provides an opportunity to efficiently manage hot carriers that are generated from metal nanostructures through surface plasmon effects for photocatalysis applications.