Gold-Palladium Bimetallic Nanoparticles for Inducing Surface Plasmon Resonance to Catalyze Ethanol Oxidation

Gold-palladium (Au-Pd) bimetallic nanoparticles were prepared as a series of alloy and core-shell nanostructures to synergistically couple plasmonic (Au) and catalytic (Pd) metals to tailor the optical and catalytic properties. Catalysts utilizing plasmonic metals that exhibit a localized surface plasmon resonance (SPR) can be harnessed for light-driven enhancement via augmented carrier generation/separation and photothermal conversion. Titania-supported Au-Pd bimetallic nanoparticles were used as catalysts to study the ethanol (EtOH) oxidation reaction, with an emphasis towards driving carbon-carbon (C-C) bond cleavage at low temperatures. Plasmonically-assisted photocatalytic oxidation of EtOH to CO2 under solar simulated-light irradiation was studied by monitoring the yield of gaseous products via suspended particle photocatalysis and electrochemical methods. Results are correlated with Au-Pd composition and homogeneity to maintain SPR-induced charge separation and mitigate the carbon monoxide poisoning effects on Pd. Under solar simulated conditions, carrier generation/separation and photothermal conversion was achieved, resulting in the photogenerated “hot” holes driving the photo-oxidation of EtOH primarily on the AuPd, providing a method to selectively cleave C-C bonds. Bimetallics provide a pathway for driving desired photocatalytic and photoelectrochemical reactions with superior catalytic activity and selectivity.