Plasmon-Induced Water Splitting System

We have successfully developed a plasmon-assisted water splitting system that operates under irradiation by visible light; the system is based on the use of two sides of the same strontium titanate (SrTiO₃) single crystal substrate. The water splitting system contains two solution chambers to separate hydrogen (H₂) and oxygen (O₂), respectively. To promote water splitting, a chemical bias was applied by pH values regulations of those chambers. The quantity of H₂ evolved from the surface of platinum, which was used as a reduction co-catalyst, was twice of O₂ evolved from an Au nanostructured surface. Thus, the stoichiometric evolution of H₂ and O₂ was clearly demonstrated. The hydrogen evolution action spectrum closely corresponds to the localized surface plasmon resonance spectrum, indicating that the plasmon-assisted charge separation at the Au/SrTiO₃ interface promotes water oxidation and the subsequent reduction of a proton on the backside of the SrTiO₃ substrate.  We have elucidated furthermore that the chemical bias is dramatically reduced by plasmonic effects, which indicate the possibility of constructing an artificial photosynthesis system with low energy consumption.