This work investigates the impact of different excitation wavelengths on photo-thermal-catalytic oxidation by Au/TiO2 nanoparticles. Catalytic performance was assessed by monitoring the CO2 yield of gas phase ethanol oxidation over a temperature range of 100 – 250 °C under either visible light or UV illumination.
Despite being a weak thermal catalyst (5% catalytic enhancement compared to neat TiO2 under thermal catalytic conditions), Au/TiO2 displayed a considerable photo-thermal-synergism in the photo-thermal regime (> 175 °C), with over 50% and 100% increases in catalytic performance compared to neat TiO2 under visible light and UV illumination, respectively.
Photo-thermal-catalytic results and detailed probing of post-reaction surface carbon species on Au/TiO2 indicated that photo-enhancement under UV illumination was due to congruent roles of the photo- and thermal- catalysis, while photo-enhancement under visible light illumination was due to plasmonic-mediated electron charge transfer from the Au deposits to the TiO2 support.
Graphical abstract of plasmonic Au/TiO2 catalyst