Charge Transfer Dynamics between Photoexcited CdS Nanorods and Mononuclear Ru Water-Oxidation Catalysts

We describe the charge transfer interactions between photoexcited CdS nanorods and mononuclear water oxidation catalysts derived from the [Ru(bpy)(tpy)Cl]+ parent structure. Upon excitation, hole transfer from CdS oxidizes the catalyst (Ru2+ → Ru3+) on a 100 ps to 1 ns timescale. This is followed by 10–100 ns electron transfer (ET) that reduces the Ru3+ center. The relatively slow ET dynamics may provide opportunities for the accumulation of multiple holes at the catalyst, which is necessary for water oxidation.