RE:Getting closer to an explanation(Phys.org)—Although scientists know that when silicon mixes with water, hydrogen is produced through oxidation, no one expected how quickly silicon nanoparticles might perform this task. As a new study has revealed, 10-nm silicon nanoparticles can generate hydrogen 150 times faster than 100-nm silicon nanoparticles, and 1,000 times faster than bulk silicon. The discovery could pave the way toward rapid "just add water" hydrogen generation technologies for portable devices without the need for light, heat, or electricity..........
...............The key advantage of silicon oxidation for hydrogen generation is its simplicity," Swihart said. "With this approach, hydrogen is produced rapidly, at room temperature, and without the need for any external energy source. The energy needed for hydrogen generation is effectively stored in the silicon. All of the energy input required for producing the silicon can be provided at a central location, and the silicon can then be used in portable applications...........
.........."The key disadvantage of silicon oxidation is its relative inefficiency. The energy input required to create the silicon nanoparticles is much greater than the energy available from the hydrogen that is finally produced. For large scale applications, this would be a problem. For portable applications, it is not. For example, the cost of electricity supplied by an ordinary household battery can easily be 10 to 100 times higher than the cost of electricity from a utility, but batteries still play an important role in our lives."