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Tunable Oxygen Activation for Catalytic Organic Oxidation: Schottky Junction versus Plasmonic Effects
Author(s) -
Long Ran,
Mao Keke,
Gong Ming,
Zhou Shan,
Hu Jiahua,
Zhi Min,
You Yang,
Bai Song,
Jiang Jun,
Zhang Qun,
Wu Xiaojun,
Xiong Yujie
Publication year - 2014
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201309660
Subject(s) - materials science , plasmon , schottky barrier , schottky diode , catalysis , nanocrystal , photochemistry , photocatalysis , electron , metal , optoelectronics , nanotechnology , chemistry , organic chemistry , physics , diode , quantum mechanics , metallurgy
The charge state of the Pd surface is a critical parameter in terms of the ability of Pd nanocrystals to activate O 2 to generate a species that behaves like singlet O 2 both chemically and physically. Motivated by this finding, we designed a metal–semiconductor hybrid system in which Pd nanocrystals enclosed by {100} facets are deposited on TiO 2 supports. Driven by the Schottky junction, the TiO 2 supports can provide electrons for metal catalysts under illumination by appropriate light. Further examination by ultrafast spectroscopy revealed that the plasmonics of Pd may force a large number of electrons to undergo reverse migration from Pd to the conduction band of TiO 2 under strong illumination, thus lowering the electron density of the Pd surface as a side effect. We were therefore able to rationally tailor the charge state of the metal surface and thus modulate the function of Pd nanocrystals in O 2 activation and organic oxidation reactions by simply altering the intensity of light shed on Pd–TiO 2 hybrid structures.