Photoassisted Overall Water Splitting In A Visible Light-absorbing Dye-sensitized Photoelectrochemical Cell

摘要

Photocatalytic water splitting uses light energy to drive the thermodynamically uphill conversion of water into its constituent elements. Fujishima and Honda reported the first example of overall water splitting with TiO_2 photoelectrodes under UV illumination in 1972, and more efficient multijunction photoelectrodes have subsequently been reported. More recently, Maeda et al. have developed a photocatalytic water splitting system based on oxyni-tride semiconductor particles. In comparison, progress on overall water splitting in molecular photosystems systems has been slow. The use of sacrificial oxidizing and reducing agents has enabled separate explorations of the hydrogen- and oxygen-evolving half-reactions. However, despite recent progress on water oxidation catalysts, the rate of hole scavenging is in general too slow to compete with back electron transfer in artificial photosynthetic systems.