Plasmonically Enhanced Hydrogen Evolution with an Al–TiO₂-Based Photoelectrode

High Resolution Image Download MS PowerPoint Slide Photoelectrochemical water splitting, as a method for producing clean hydrogen, could benefit from both plasmon-enhanced processes and the incorporation of earth-abundant materials in photoelectrode design. Here we report a n-TiO 2 /aluminum (Al) nanodisk/p-GaN photoelectrode sandwich device that exhibits enhanced H 2 generation efficiencies due to a combination of plasmon-enhanced processes. Hot electrons generated in the illuminated Al nanodisk are injected into the conduction band of the TiO 2 layer, subsequently transferring into water molecules adsorbed on the TiO 2 surface, driving H 2 evolution. The photocurrent densities we observe are nearly an order of magnitude higher than in an equivalent device with the Al nanodisk replaced with a Au nanodisk of the same size and are on par or better than previous reports of plasmonic photoelectrodes using Au nanoparticles in combination with cocatalyst species.