Siナノ粉末と中性水の反応による水素生成メカニズムの検討
Silicon nanopowder prepared by a bead-milling technique was found to react with water across a neutral pH range (7.0–8.6), producing molecular hydrogen without requiring strongly alkaline conditions. At pH 8.0, approximately 55 ml of hydrogen per gram of Si was generated within one hour, an amount equivalent to the hydrogen dissolved in roughly 3 L of saturated hydrogen-rich water. Reaction kinetics showed strong dependence on both pH and the crystallite size of the nanopowder, but not on aggregate size, indicating that hydroxide ions serve as the rate-limiting reactant. A two-step mechanism was proposed: Si nanopowder reacts with hydroxide ions to yield hydrogen, silicon monoxide, and conduction-band electrons; these electrons are subsequently captured by water molecules, regenerating hydroxide ions and additional hydrogen. The negligible net change in pH after the reaction supports this cyclic mechanism. Because Si and its oxides exhibit low toxicity, the authors suggest potential in vivo applicability of this system for intracorporeal hydrogen generation aimed at scavenging hydroxyl radicals.
Si nanopowder reacts with hydroxide ions to produce H2, SiO, and conduction-band electrons; those electrons are then accepted by water molecules, regenerating H2 and hydroxide ions in a cyclic, pH-buffered mechanism.
This is basic research at the cellular or molecular level. For human application, inhalation is the most promising delivery route, but inhalation carries explosion risk and concentration matters (empirical LFL of 10%; high-concentration devices are not recommended).
See also:
https://h2-papers.org/en/papers/28579914