I wrote: One question I have concerns the thermal properties of the [carbon nanotube > bulk] system. I have started to conclude that the thermal properties are > important -- for example, perhaps the temperature in the substrate must > gradually build to the point where some kind of resonance is triggered in > smaller sites throughout the material. It is not difficult to envision how > this might occur in a thermally conducting material such as a metal. It is > harder to see how this would happen in a carbon substrate. >
On second thought, graphene has some interesting thermal properties, as do carbon nanotubes: http://en.wikipedia.org/wiki/Graphene#Thermal_properties http://authors.library.caltech.edu/1745/1/CHEnano00.pdf http://en.wikipedia.org/wiki/Thermal_properties_of_nanostructures#Carbon_nanotubes Wikipedia gives the thermal conductivity of nickel as 90.9 W/m/K. There are different numbers for the thermal conductivity of carbon nanotubes. The second source mentions up to ~29 W/m/K, provided there are few defects. The third source, from Wikipedia, says that the conductivity can get up to 3500 W/m/k, two orders of magnitude higher. But even if the carbon substrate were coal, it's obvious that it would have interesting thermal properties. Another important property would be the ability to load hydrogen. Apparently it might be possible to store hydrogen in carbon nanotubes: http://www.rsc.org/chemistryworld/News/2011/January/26011103.asp How high a loading can be obtained in the structure that is discussed in this source is unclear. In the model in my mind, the cavity would probably need to be filled with hydrogen. If the rate of desorption of hydrogen is too high, a reaction might not be possible according to this line of thinking. A very nice thing about carbon bulk is that it can sustain high temperatures. The temperatures mentioned in the third link above, to Wikipedia, for "temperature stability," are 2800 C (3073 K) in a vacuum and 750 C (1023 K) in air. The following source gives a melting temperature for carbon nanotube material without defects of 4500 K and a pre-melting temperature of 2600 K. http://iopscience.iop.org/0957-4484/18/28/285703;jsessionid=D53B81E04C8D46A0D606206C1E32DF70.c2 By comparison, the melting point of nickel is 1728 K. The reason the higher temperature would be useful in this line of reasoning is that a higher frequency of infrared would permeate the bulk. One might even have a fun time taking coal and heating it in a chamber loaded with hydrogen (but doing so very carefully). I believe Less Case did an interesting experiment with activated carbon that was reproduced by Michael McKubre. It included a palladium "catalyst," but the palladium might not have been essential to the experiment if a suitable carbon material had been used. Activated carbon is carbon that has a large number of small pores and therefore a high surface area. If carbon nanotube material with some of these exotic properties, such as high thermal conductivity, high magnetic fields, and optical resonance, was used, a transition metal might not be needed. Eric
