Nanosilicon in water as a source of hydrogen: size and pH matter.

We report on the interaction of silicon nanocrystals with water/alcohol solutions which results in their complete oxidation, the hydrolysis of water and hydrogen generation in amounts close to the ideal scenario. Water acts as an oxidizer while alcohol is required for efficient wetting of nanosilicon. This process results in the formation of silicon-based alcogel which can be further transferred to aerogel.