Efficient Hydrogen Production by a Photoredox Cascade Catalyst Comprising Dual Photosensitizers and a Transparent Electron Mediator
Nobutaka Yoshimura, Masaki Yoshida, Atsushi Kobayashi
Abstract
One-directional electron transport between a photocatalyst and redox mediator is crucial for achieving highly active Z-scheme water-splitting photocatalysis. Herein, a photoredox cascade catalyst that artificially mimics the electron transport chain in natural photosynthesis was synthesized from a Pt-TiO 2 nanoparticle catalyst, two photosensitizers ( RuCP 6 and RuP 6 ), and a visible-light-transparent electron mediator ( HCRu ). During photocatalytic hydrogen evolution in the presence of a redox-reversible electron donor, [Co(bpy) 3 ] 2+ (bpy = 2,2′-bipyridine), the HCRu -Zr- RuCP 6 -Zr- RuP 6 @Pt-TiO 2 ( PRCC-1 ) photocatalyst exhibited the highest reported initial (1 h) apparent quantum yield ( i AQY = 2.23%) of dye-sensitized TiO 2 photocatalysts to date. Furthermore, PRCC-1 successfully produced hydrogen when using hydroquinone monosulfonate (H 2 QS – ) as the hydrogen source.