Construction of Nanostructured Cobalt Oxide Thin Films
Construction of Nanostructured Cobalt Oxide Thin Films
Construction of Nanostructured Cobalt Oxide Thin Films
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<strong>Construction</strong> <strong>of</strong><br />
<strong>Nanostructured</strong> <strong>Cobalt</strong><br />
<strong>Oxide</strong> <strong>Thin</strong> <strong>Films</strong><br />
Jordan Maron<br />
Jamie Neilson<br />
Daniel Morse<br />
Biomolecular Science and Engineering
Why Study <strong>Cobalt</strong> <strong>Oxide</strong><br />
Energy application: photocatalytic water<br />
splitting – generating hydrogen fuel from light<br />
2H 2 O 2H 2 + O 2<br />
light<br />
Co 3 O 4<br />
Enabled by:<br />
<strong>Cobalt</strong> <strong>Oxide</strong><br />
Powder<br />
• Atomic structures with Co(III), e.g. Co 3 O 4<br />
• Morphology with high surface area<br />
<strong>Cobalt</strong> <strong>Oxide</strong><br />
Atomic Structure
<strong>Cobalt</strong> <strong>Oxide</strong> Background<br />
Usually produced with irregular<br />
morphology and microstructure<br />
• Hard to characterize<br />
Our method <strong>of</strong> synthesis allows for<br />
control <strong>of</strong> morphology on the nano<br />
scale<br />
• More useful for proposed applications
My Project Goal<br />
Find which cobalt counter ion and<br />
annealing temperature produce the<br />
most crystalline cobalt oxide sample<br />
with the highest specific surface area<br />
derived from a nanostructured<br />
architecture
Experimental Methods<br />
<br />
<br />
<br />
Synthesize cobalt hydroxide by reacting various CoA x<br />
precursors with ammonia via vapor diffusion<br />
• <strong>Cobalt</strong> chloride<br />
• <strong>Cobalt</strong> perchlorate<br />
• <strong>Cobalt</strong> sulfate<br />
• <strong>Cobalt</strong> iodide<br />
Sample Treatment:<br />
• One substrate left as is<br />
• One put in 180°C oven<br />
• One put in 500°C furnace<br />
• One put in 800°C furnace<br />
Analysis and characterization
Experimental Methods Visual<br />
Start<br />
Finish
Characterization<br />
Two machines are used<br />
• X-Ray diffractometer<br />
• Scanning electron microscope<br />
Used to identify compound and<br />
analyze its morphology
X-Ray Diffraction<br />
Control: Alfa Aesar cobalt oxide
X-Ray Data Continued<br />
<strong>Cobalt</strong> chloride precursor<br />
Quartz<br />
Amorphous<br />
Amorphous<br />
<strong>Cobalt</strong> Hydroxide
X-Ray Data Continued<br />
<strong>Cobalt</strong> perchlorate precursor<br />
<strong>Cobalt</strong> Hydroxide<br />
Both <strong>Cobalt</strong> <strong>Oxide</strong><br />
Amorphous
Scanning Electron<br />
Microscopy<br />
Control: Alfa Aesar cobalt oxide<br />
Relatively unstructured morphology
SEM Data Continued<br />
<strong>Cobalt</strong><br />
chloride<br />
precursor<br />
Individual platelets<br />
at all temperatures<br />
Notice strange Swisscheese<br />
platelet<br />
morphology in 900°C<br />
sample
SEM Data Continued<br />
Varying morphology<br />
at all temperatures<br />
<strong>Cobalt</strong><br />
perchlorate<br />
precursor<br />
Very interesting porous<br />
nanostructure - cause<br />
unknown
Results Summary<br />
Precursor Salt As Prepared 180°C 500°C 800°C<br />
Chloride α Co(OH) 2<br />
Platelets<br />
Amorphous<br />
Platelets<br />
Amorphous<br />
Platelets<br />
N/A (900°C)<br />
Porous<br />
platelets<br />
Perchlorate α Co(OH) 2<br />
Web<br />
Amorphous<br />
Web<br />
Co 3 O 4<br />
Porous<br />
nanostructure<br />
Co 3 O 4<br />
Pillar<br />
nanostructure<br />
Sulfate α Co(OH) 2<br />
Web<br />
α Co(OH) 2<br />
Web<br />
Amorphous<br />
Web<br />
Co 3 O 4<br />
Globular<br />
microstructure<br />
Iodide α Co(OH) 2<br />
Web<br />
Co 3 O 4<br />
Web<br />
Co 3 O 4<br />
Web<br />
Co 3 O 4<br />
Globular Web
Conclusions<br />
Both counter ion and annealing<br />
temperature determine material<br />
properties:<br />
• Determines morphology<br />
• Crystal orientation<br />
• Atomic structure<br />
Larger counter ions decrease annealing<br />
temperature needed and increases<br />
microporosity
Future Exploration<br />
Perform a second trial with each precursor<br />
to see whether or not the results can be<br />
reproduced or improved<br />
Investigate causes <strong>of</strong> certain morphologies<br />
Test performance <strong>of</strong> our cobalt oxide and<br />
compare to that <strong>of</strong> commercially available<br />
cobalt oxide<br />
Analyze with transmission electron<br />
microscope<br />
Measure specific surface area
Reflections<br />
I got a taste <strong>of</strong> what it is like to do graduate research in<br />
a real laboratory<br />
I confirmed for myself that pursuing a career in the<br />
sciences seems to be the right path for me take<br />
I loved getting to use all the really fancy equipment
Acknowledgements<br />
Jamie Neilson and Birgit Schwenzer for being my<br />
mentors<br />
Pr<strong>of</strong>essor Daniel Morse for allowing me to work in<br />
his department<br />
California NanoSystems Institute, Institute for<br />
Collaborative Biotechnologies, Department <strong>of</strong><br />
Energy, and National Science Foundation for funding<br />
the research<br />
Lubi, Anthony, and Herb for organizing the program
<strong>Construction</strong> <strong>of</strong><br />
<strong>Nanostructured</strong> <strong>Cobalt</strong><br />
<strong>Oxide</strong> <strong>Thin</strong> <strong>Films</strong><br />
Jordan Maron<br />
Jamie Neilson<br />
Daniel Morse<br />
Biomolecular Science and Engineering
X-Ray Data<br />
<strong>Cobalt</strong> sulfate precursor<br />
Notice consistency between trials<br />
<strong>Cobalt</strong> oxide confirmed in matching 800°C samples<br />
500°C contained one cobalt oxide peak<br />
As is and 180°C shown to contain cobalt hydroxide
SEM Data<br />
<strong>Cobalt</strong><br />
sulfate<br />
precursor<br />
Globule Morphology
X-Ray Data<br />
<strong>Cobalt</strong> iodide precursor<br />
Co 3 O 4<br />
Co 3 O 4<br />
Disordered Co 3 O 4<br />
<strong>Cobalt</strong> Hydroxide
SEM Data<br />
<strong>Cobalt</strong> iodide<br />
precursor<br />
Morphology resembles<br />
that <strong>of</strong> the 800°C<br />
sulfate sample
TGA Data<br />
Chloride Sample
TGA Data<br />
Perchlorate Sample
TGA Data<br />
Sulfate Sample
TGA Data<br />
Iodide Sample
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