Photocatalytic Hydrogen Production with Tunable Nanorod Heterostructures

We report the design of a multicomponent nanoheterostructure aimed at photocatalytic production of hydrogen. The system is composed of a platinum-tipped cadmium sulfide rod with an embedded cadmium selenide seed. In such structures, holes are three-dimensionally confined to the cadmium selenide, whereas the delocalized electrons are transferred to the metal tip. Consequently, the electrons are now separated from the holes over three different components and by a tunable physical length. The seeded rod metal tip samples studied here facilitate efficient long-lasting charge carrier separation and minimize back reaction of intermediates. By tuning the nanorod heterostructure length and the seed size, we were able to significantly increase the activity for hydrogen production compared to that of unseeded rods. This structure was found to be highly active for hydrogen production, with an apparent quantum yield of 20% at 450 nm, and was active under orange light illumination and demonstrated improved stability compared to CdS rods without a CdSe seed.