-----Original Message----- From: Michel Jullian [ > Or rather, as it turns out, exactly right. Physics works, contrary to your suggestions :)
It works of course, but not as perfectly as you suggest, in real world applications. > Besides, you don't have to take my word, see http://en.wikipedia.org/wiki/Heat_of_combustion Hydrogen: 140 kJ/g, which is about 1.5eV per atom. Yes, but once again your reference is NOT to "burning hydrogen in air". At the very top of the page you site, it clearly says "The heat of combustion is the energy released as heat when one mole of a compound undergoes complete combustion with oxygen...." Burning H2 in air is not "complete combustion with oxygen" and in fact H2 can be leaned-out sufficiently in air so that it will not burn at all. Contrary to what you state, parasitic loses cannot be ignored - unless you are merely trying to prove a pedantic point, which seems to be the case. > The important result here is that the 2 eV you get by letting an hydrogen atom bond to the _surface_ of a Pd nanoparticle are comparable with the chemical energy you get by letting it bond to an oxygen atom (starting from molecular gas phase in both cases) NO! Absolutely not a relevant comparison, nor an accurate value. Otherwise metal hydrides could not be used for hydrogen storage, and palladium could not be used as a filter to separate H2 from other gases, both of which applications are common. Imagine having to apply 2 eV of thermal energy to a metal hydride in order to release the stored hydrogen gas for use in an engine. That is absurd. Jones
