Plasmon-Induced Water Splitting System

Tuesday, 7 October 2014: 10:40
Sunrise, 2nd Floor, Mars 1-4 (Moon Palace Resort)
H. Misawa (Research Institute for Electronic Science, Hokkaido University)
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.