Abstract:
Harvesting the full bandwidth of the solar spectrum, especially the near infrared portion, remains a challenge for solar-to-fuel conversion technology. Plasmonic nanostructures have recently attracted attention in this connection due to their enhanced yet tunable broadband absorption and photochemical stability. Here we report a nanoplasmonic photocatalytic construct by decorating plasmonic Au Nanorods with CoO for harvesting visible and NIR light via photo-electrochemical water oxidation reaction (WOR). In contrast to previous reports of plasmonic photocatalyst constructs, our structure does not require complicated fabrication or rely on rare-earth heavy-atom elements and exhibits excellent photostability without leaching of either cobalt or gold into the reaction solution under photoelectrochemical conditions. This catalytic construct triggered photo-electrochemical WOR with generation of significant photocurrent (~ 100 �Acm-2) while producing photogenerated oxygen at 18.1 mmoles h-1 of and hydrogen at 40.2 mmoles h-1 (on counter electrode) per miligram of cobalt under broadband excitation of 410-1700 nm with photon to oxygen conversion efficiency of ~0.05% in neutral aqueous conditions. The broadband photocatalytic activity of CoO-decorated Au Nanorod was attributed to the hot holes generated by the photoexcitation of plasmonic gold nanorods.