Interconversion of Inverse Opals of Electrically Conducting Doped Titanium Oxides and Nitrides

There is a need for conducting, porous, and chemically stable materials for technologies including, but not limited to, fuel cells, solar cells, and batteries. The need for catalyst support materials that are more durable than carbon black in fuel cells motivated previous studies of the synthesis, c...

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Bibliographic Details
Published in:Small (Weinheim an der Bergstrasse, Germany) Germany), 2012-09, Vol.8 (18), p.2824-2832
Main Authors: Subban, Chinmayee V., Smith, Ian C., DiSalvo, Francis J.
Format: Article
Language:English
Subjects:
conductivity
inverse opals
nanoparticles
nitrides
oxides
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Summary:There is a need for conducting, porous, and chemically stable materials for technologies including, but not limited to, fuel cells, solar cells, and batteries. The need for catalyst support materials that are more durable than carbon black in fuel cells motivated previous studies of the synthesis, characterization, and corrosion resistance of Ti0.7W0.3O2 nanoparticles. However, because even higher porosity and increased electrical conductivity are desired, processes were developed to prepare rutile phase Ti0.7W0.3O2 and cubic Ti0.7W0.3N in inverse opal morphologies from a precursor inverse opal of very poorly conducting, amorphous Ti0.7W0.3O2.3. Inverse opals have been explored for a variety of applications from catalysis to photonics, and inverse opals of both oxides and nitrides have been reported. By synthesizing highly conducting mixed‐metal oxides and mixed‐metal nitrides, the applications of inverse opals can be broadened. Herein, the synthesis and characterization of polystyrene‐templated, single‐phase, crystalline inverse opals of Ti0.7W0.3O2 are reported. These conducting inverse opals can subsequently be converted to inverse opals of Ti0.7W0.3N and then fully oxidized back to inverse opals of the original insulating, amorphous Ti0.7W0.3O2.3. Such changes in composition and crystal structure, while successfully retaining the inverse opal morphology without the use of a supporting template during the conversion, have not been previously reported. Interconversion of inverse opals of fully oxidized product (Ti0.7W0.3O2.3) to reduced product (Ti0.7W0.3O2) to nitride product (Ti0.7W0.3N) and back to fully oxidized product (Ti0.7W0.3O2.3) is described. These transitions involve changes in oxidation state, chemical composition, and crystal structure. By controlling the processing conditions, the inverse opal morphology of the samples is retained.
ISSN:1613-6810
1613-6829
DOI:10.1002/smll.201200502