Capped semiconductor colloids. Synthesis and photoelectrochemical behavior of TiO{sub 2}-capped SnO{sub 2} nanocrystallites

Journal Article · Thu Jun 01 04:00:00 EDT 1995 · Journal of Physical Chemistry

DOI:https://doi.org/10.1021/j100022a035· OSTI ID:68005

Bedja, I; Kamat, P V ^[1]

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1. Univ. of Notre Dame, IN (United States)

In our continuing efforts to surface-modify semiconductor colloids, we have succeeded in preparing TiO{sub 2}-capped SnO{sub 2} (SnO{sub 2} @ TiO{sub 2}) and TiO{sub 2}-capped SiO{sub 2} (SiO{sub 2} @ TiO{sub 2}) colloids. The SnO{sub 2} @ TiO{sub 2} colloids are 80-100 A in diameter and exhibit improved photochromic and photocatalytic efficiencies compared to the native colloids. The improved charge separation in this system was confirmed from the enhanced efficiency of hole trapping monitored from the absorption peak at 360 nm. The photocatlytic properties of SiO{sub 2} @ TiO{sub 2} colloids are similar to that of native TiO{sub 2} colloids. The capped semiconductor systems are useful for the oxidation of I{sup -} and SCN{sup -}. For example, the quantum efficiency for I{sup -} oxidation can be improved by a factor of 2-3 upon capping the SnO{sub 2} colloids with TiO{sub 2}. The distinction between the capped and coupled semiconductor systems has been made by preparing nanocrystalline thin films in two different geometries and studying their photoelectrochemical behavior. 54 refs., 9 figs.

• Sponsoring Organization: USDOE
• OSTI ID: 68005
• Journal Information: Journal of Physical Chemistry, Journal Name: Journal of Physical Chemistry Journal Issue: 22 Vol. 99; ISSN JPCHAX; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
CHARGE TRANSPORT
COLLOIDS
ELECTROCHEMISTRY
PHOTOCHEMICAL REACTIONS
PHOTOLYSIS
SEMICONDUCTOR MATERIALS
SURFACE TREATMENTS
SYNTHESIS
THIN FILMS
TIN OXIDES
TITANIUM OXIDES