Carbon Nanotubes and Graphene - Research and Applications

Researchers have shown that under UV-irradiation, the addition of single wall carbon nanotubes (SWCNTs) to TiO₂ induces a substantial synergy effect. Deposition of TiO₂ on SWNTs surface may give better results for H₂ generation.The photocatalytic H₂ gas production from water/alcohol mixtures, was investigated. The amount of H₂ gas increased by a factor of ca. 400 simply due to mixing SWCNTs with TiO₂.
Source: Catalysis Communications (2008), article in press

Carbon nanotubes decorated by a high density of carbon nanoparticles of turbostratic stacked graphenes are fabricated by the hydrocarbon ion deposition with energy of 80 eV at 700 degrees C. The formation of carbon nanoparticles of turbostratic stacked graphenes is by virtue of the structure reconstruction driven by the high temperature annealing effect. There are two competing effects by the ion irradiation. One is the deposition effect of the carbon-based ions and the other is the etching effect by the hydrogen ions. At low hydrogen content in the gas phase, the deposition rate of carbon-based ions is faster than the etching rate by the hydrogen ions and CNTs are coated by carbon nanoparticles of turbostratic stacked graphenes. The nanoparticles extend from the nanotube surface and have a random distribution on the surface of CNTs at first. With the increasing duration of deposition, the whole surface of CNTs is coated by carbon nanoparticles of turbostratic stacked graphenes at last. Meanwhile, the size of nanoparticles decreases with the increasing hydrogen content. At intermediate hydrogen content, the etching effect is prominent and the structural quality of carbon nanoparticles of turbostratic stacked graphenes remains low, while amorphous structure begins to be introduced. At high hydrogen content, CNTs are exposed to the hydrogen ions and are etched into pieces of carbon particles, built from relatively steady sp3 bond carbon atoms.
Source: Carbon (2008), article in press

A metal hydride-based hydrogen-storage device was developed capable of storing 70 l of hydrogen reversibly at ambient conditions. Fabrication of multi-walled carbon nanotube (MWNTs)-based fuel cell stack and microfuel cell were done using membrane electrode assembly, prechanneled bipolar plates and printed circuit boards, respectively. The MWNTs were synthesized by pyrolysis of acetylene. Functionalization of MWNTs results in improved adhesion of Pt nanoparticles of around 3–5 nm diameter on to the MWNTs surface.

Performance studies of fuel cell stack and microfuel cell were done by coupling them to hydrogen-storage device followed by the demonstration of working of electronic devices. Serial configured fuel cell stack gives a maximum power density of 500mW/cm2 at 1.75V, whereas planar configured microfuel cell gives a maximum power density of 125mW/cm2 at 2.0V (H2/O2) and 68mW/cm2 at 2.0V (H2/air).
Source: International Journal of Hydrogen Energy 32 (2007) 4272 – 4278