Part 2 - Carbon nanofibres Flashcards
Give some examples of carbon nanostructures.
Carbon nanotubes
Graphene
Fullerenes
Carbon nanofibers
What are some carbon nanofibres structures that can form?
Platelet Platelet (spiral) Fishbone, hollow core Fishbone, solid Ribbon Stacked cup
What are some great properties of graphene?
High conductivity
High surface area
High thermal and mechanical properties
What are the different configurations of nanotubes?
Zigzag, armchair and chiral.
How does the mechanical properties of CNTs compare with steel?
Five times higher Young’s modulus.
10-30 times higher tensile strength
What are the general way to synthesize carbon nanostructres?
Decomposition of hydrocarbons, using plasma arc, laser ablation or catalytic decomposition.
How can carbon nanotubes grow?
By using a metal catalyst as a sort of root, and letting it grow upwards.
Why would we want to further functionalize the carbon nanotubes?
They are:
- difficult to disperse
- insoluable in water and organic media
- resistant to wetting
- need to remove catalyst
What are some typical applications for carbon nanostructures?
Electro-catalyst support Fuel cells Supercapacitors Batteries Composite materials Construction, marine, aeronautics Electronics Storage of electric charge Nanofiltration Carbon membranes
What types of fuel cells can carbon nanostructures be used for? How are they incorporated?
Polymer electrolyte / membrane fuel cells (PEMFC)
Direct methanol fuel cell (DMFC)
As support for electrocatalyst.
Why are carbon nanofibres desireable for electrocatalysis?
More active Resistance to CO poisoning. High metal dispersion High electroactive surface area values 3D mesoporous network Excellent conducting properties
What are the criteria for fuel cell electrocatalysts?
High electron conductivity
High level of mesoporosity
Suitable morphology
Good hydrophobicity for removal of water
What type of nanofibres are desirable for electrocatalyst support?
Platelet CNFs.
What is cyclic voltammetry?
The most useful technique in electrochemistry. Can provide qualitative information about catalysts and electrochemical reactions, such as the response of catalysts and the catalyst activity of the catalyst with respect to some electrochemical reactions.
How can carbon nanostructures be used in Li-ion batteries?
As a constituent of the cathode. The standard LiCoO2 are costly and degradates.
