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

Abstract

Abstract Hematite nanoflake arrays were decorated with Au nanoparticles through a simple solution chemistry approach. We show that the photoactivity of Au‐decorated Fe 2 O 3 electrodes for photoelectrochemical water oxidation can be effectively enhanced in the UV/Visible region compared with the bare Fe 2 O 3 . Au‐nanoparticle‐decorated Fe 2 O 3 nanoflake electrodes exhibit a significant cathodic shift of the onset potential up to 0.6 V [vs. reversible hydrogen electrode (RHE)], and a two times increase in the water oxidation photocurrent is achieved at 1.23 V RHE . A maximum photocurrent of 2.0 mA cm −2 at 1.6 V RHE is obtained in 1 M KOH under AM 1.5 (100 mW cm −2 ) conditions. The enhancement in photocurrent can be attributed to the Au nanoparticles acting as plasmonic photosensitizers that increase the optical absorption.