Photocatalytic water splitting has been improved in this work by exploiting a Au/TiO2–Fe2O3 plasmonic cocatalyst system. A 5-fold improvement of water splitting photocurrent was observed in the Au/TiO2–Fe2O3 photoelectrode compared to that of iron oxide only. In order to investigate the enhanced mechanism of this plasmonic cocatalyst system, different plasmonic photoelectrodes were systematically examined under different visible light lasers. The crystallography of the TiO2–Fe2O3 cocatalyst was characterized by high-resolution transmission electron microscopy (HRTEM) and X-ray diffractometer (XRD). UV-visible spectroscopy (UV-vis) was employed to determine the plasmon enhanced absorption of photoelectrodes. In addition, a spatially controllable plasmon enhanced water splitting photocurrent was demonstrated in this study.
