Plasmon-Enhanced Photoelectrochemical Water Splitting Using Au Nanoparticles Decorated on Hematite Nanoflake Arrays

Hematite nanoflake arrays were decorated with Au nanoparticles through a simple solution chemistry approach. We show that the photoactivity of Au-decorated Fe2O3 electrodes for photoelectrochemical water oxidation can be effectively enhanced in the UV/Visible region compared with the bare Fe2O3. Au-nanoparticle-decorated Fe2O3 nanoflake electrodes exhibit a significant cathodic shift of the onset potential up to 0.6V [vs. reversible hydrogen electrode (RHE)], and a two times increase in the water oxidation photocurrent is achieved at 1.23V(RHE). A maximum photocurrent of 2.0mAcm(-2) at 1.6V(RHE) is obtained in 1M KOH under AM1.5 (100mWcm(-2)) conditions. The enhancement in photocurrent can be attributed to the Au nanoparticles acting as plasmonic photosensitizers that increase the optical absorption.