Scientists at the University at Buffalo in New York have managed to use silicon nanoparticles to form hydrogen from water at a much faster rate than was previously thought possible. The researchers compared the rate of this reaction using silicon particles of varying sizes.
They found that particles of 10nm diameter caused the reaction to proceed approximately 150 times faster than those of 100nm diameter, despite there being just a 6-fold increase in surface area for the smaller particles. They attributed this unexpectedly high rate of increase to the change in geometry of the particles as the silicon reacts. This suggests that the smaller (10nm) particles decrease in size without changing shape, while the silicon in the larger particles reacts in an uneven way to form hollow shells or capsules.
It is hardly surprising that the scientists are already looking forward to potential uses for this form of hydrogen generation: the reaction does not require heat, light or electricity and only produces non-toxic silicic acid as a byproduct. Researcher Paras Prasad, executive director of UB’s Institute for Lasers, Photonics and Biophotonics (ILPB) has suggested this technology could lead to a “just add water” approach to generating hydrogen on demand.
Unfortunately the current cost in producing such tiny particles (10nm diameter equates to particles of only a couple of hundred atoms across) means that use of this technology would currently be restricted to applications where portability rather than cost are key, such as military uses or on very remote expeditions. However, with further research into scalable and energy-efficient production of the silicon nanoparticles, there is no reason why this technology should not come into wider use in the future.
