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Size Effects on Photocatalytic H2 Generation with CdSe/CdS Core-Shell Nanocrystals
Ist Teil von
Zeitschrift für physikalische Chemie (Neue Folge), 2015-02, Vol.229 (1), p.205-219
Ort / Verlag
Munich: De Gruyter Oldenbourg
Erscheinungsjahr
2015
Link zum Volltext
Quelle
De Gruyter journals
Beschreibungen/Notizen
CdSe/CdS core-shell nanocrystals with controlled
CdS shell thickness and CdSe core size were synthesized
for several different values of these two parameters. The particles in
aqueous dispersion were in situ decorated with Ni nanoparticles
and evaluated for photocatalytic hydrogen generation capacity. The
highest H
production quantum yield at 457 nm
illumination was 4.7%, while at 530 nm it rose to
9.1%. We have found that ensuring equal absorption at
illumination wavelength the H
formation rate increases with
the shell thickness, but decreases with the increasing core
size. Interestingly, the same trend was observed for the
photoluminesce quantum yield and lifetime for samples without
Ni decoration, suggesting that they reflect the balance between
charge transfer and avoidance of recombination sites which is crucial
for photocatalysis with semiconductor nanocrystals. Moreover, the
core-shell nanocrystals constitute a very convenient model system in
which the charge carrier dynamics in photocatalytic applications can
be studied. In comparison with well-known CdSe/CdS
dot-in-rod structures they are less efficient at blue illumination,
but they allow for significant extension of the usable absorption
range.