stolfi@jumbo.dec.com (Jorge Stolfi) (04/05/89)
I vaguely recall a posting to sci.space several months ago saying that the chemical reaction H + H -> H2 is very exothermic, to the point that atomic hydrogen---if it could be stored in large quantities---would make an even better rocket fuel than H2 + F2. If this is true, maybe this explains the amazing amounts of energy claimed by Fleischman and Pons. A block of palladium saturated with atomic hydrogen in close to 1:1 atomic ratio may well pack more chemical energy than the same volume of TNT. This seems enough to blow up a lab bench and blast small holes in concrete. From my armchair laboratory, I conjecture that hydrogen can be absorbed into palladium in two forms, as isolated atoms (as in the F&P experiment) or as H2 molecules (as in the usual pressure-driven absorption). In the F&P experiment, once the electrode is saturated with atomic hydrogen, any additional H atoms that are forced into it will react exothermically with the absorbed H to form adsorbed H2. This could be the source of the extra heat measured at low-power experiments. The power surges and explosions could also be explained if the single-H hydride is less stable than the H2 form at higher temperatures. In fact, it could also explain why power surges happen when the current is reduced (particularly with spongy electrodes): the atomic H starts to diffuse out of the palladium, and recombines as soon as it reaches the surface. The heat thus produced raises the temperature of the eletrode, which drives more H out, which produces more heat, and so on. If this makes sense, then the extra energy detected by F&P is energy that was stored into the electrode during the charging period. I believe that in normal electrolysis the reactions at the hydrogen electrode are something like this H3O+ + e- + electrical energy --> H2O + H H + H --> H2 + heat which add up to 2H3O+ + 2e- + electrical energy --> 2H2O + H2 + heat In the F&P experiment, during the "charging" phase, the reactions are something like H3O+ + e- + electrical energy --> H2O + H H + Pd --> PdH (single-H form) and during the "production" phase 2 (PdH) --> Pd2H2 (molecular-H form) + heat Does this make any sense? (As you can tell, I am no chemist.) Jorge Stolfi @ DEC Systems Research Center --------------------------------------------------------------------------- On the whole, though, the reaction was excellent in the scientific world, and from there it passed on to the general public who took a passionate interest in the question. That was important, since the masses were expected to subscribe huge sums. --Verne, _From the Earth to the Moon_ (1865) --------------------------------------------------------------------------- DISCLAIMER: see previous message.