Designing a photocatalytic water splitting system using nanoheterostructures

Hydrogen fuel production from photocatalytic water splitting using solar energy is a promising source of clean and renewable energy. Finding a highly efficient, stable semiconductor system with a suitable band gap and redox potential to drive the reaction with visible light absorption remains a challenge. We present a synthetic approach for such a system, which consists of a platinum (Pt)-tipped cadmium sulfide (CdS) rod, grown off the cadmium selenide (CdSe) of a CdSe- ruthenium dioxide (RuO₂) dimer. The holes are three dimensionally confined to the CdSe and can then be transferred to the RuO₂, whereas the delocalized electrons in the CdS are transferred to the Pt. This promotes charge separation and minimizes unwanted back reaction of intermediates. Water reduction occurs over the Pt while water oxidation should occur over the RuO₂.