ja303698e_si_001.pdf (1.82 MB)
Download fileNear Unity Quantum Yield of Light-Driven Redox Mediator Reduction and Efficient H2 Generation Using Colloidal Nanorod Heterostructures
journal contribution
posted on 2012-07-18, 00:00 authored by Haiming Zhu, Nianhui Song, Hongjin Lv, Craig L. Hill, Tianquan LianThe advancement of direct solar-to-fuel conversion technologies
requires the development of efficient catalysts as well as efficient
materials and novel approaches for light harvesting and charge separation.
We report a novel system for unprecedentedly efficient (with near-unity
quantum yield) light-driven reduction of methylviologen (MV2+), a common redox mediator, using colloidal quasi-type II CdSe/CdS
dot-in-rod nanorods as a light absorber and charge separator and mercaptopropionic
acid as a sacrificial electron donor. In the presence of Pt nanoparticles,
this system can efficiently convert sunlight into H2, providing
a versatile redox mediator-based approach for solar-to-fuel conversion.
Compared to related CdSe seed and CdSe/CdS core/shell quantum dots
and CdS nanorods, the quantum yields are significantly higher in the
CdSe/CdS dot-in-rod structures. Comparison of charge separation, recombination
and hole filling rates in these complexes showed that the dot-in-rod
structure enables ultrafast electron transfer to methylviologen, fast
hole removal by sacrificial electron donor and slow charge recombination,
leading to the high quantum yield for MV2+ photoreduction.
Our finding demonstrates that by controlling the composition, size
and shape of quantum-confined nanoheterostructures, the electron and
hole wave functions can be tailored to produce efficient light harvesting
and charge separation materials.