465313 Design of Heterostructure Alloy Nanoparticles for Photocatalysis of CO2 Reduction

Wednesday, November 16, 2016: 3:40 PM
Continental 1 (Hilton San Francisco Union Square)
Doh C. Lee, Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, South Korea

Semiconductor nanocrystals of size in the strong quantum confinement regime, or quantum dots, exhibit size-dependent energy gap. The size-tunable shift of band-edge states can be a powerful tool in the control of exciton dynamics. For example, heterostructure nanocrystals with mere changes in geometric dimensions can lead to the band alignment from type I to type II, which could dramatically increase the exciton recombination lifetime.[1] In this presentation, I describe the design of heterostructure nanocrystals showing long exciton recombination lifetime. For the study, we synthesized various core/shell composite particles (e.g., PbSe/CdSe or CdSe/TiO2) and introduced CdS outer-most shell with varying thickness and morphology. [2] These heterostructure nanoparticles with prolonged exciton lifetime result in efficient photocatalysis of methylene blue reduction and hydrogen evolution from water.

In the way of addressing the heterostructures, we stumbled upon the observation that metal cocatalysts and surface can be engineered with relatively simple chemical approaches, rendering new photocatalytic systems suited in photocatalytic reduction of CO2 in gas phase. [3]



[1] Lee D C, Robel I, Pietryga J M and Klimov V I 2010 J. Am. Chem. Soc. 132 9960

[2] Lee S, Lee K, Shin D J, Kim W D, Lee S and Lee D C 2014 J. Phys. Chem. C 118 23612

[3] Jeong S, Lee S, Kim W D, Lee K, Lee S and Lee D C 2016 ChemCatChem in print

[4] Lee S, Jeong S, Kim W D, Lee K, Lee S and Lee D C 2016 Nanoscale in print

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