Atmosphere-Dependent Hydrogen Release from Layered Hydrogen Silicane under Visible-Light Irradiation

Abstract Layered hydrogen silicane (L-HSi) was investigated as a visible-light-responsive hydrogen carrier. Hydrogen evolution was observed under visible-light irradiation, reaching release ratios of 8% in argon and 15% in air after 7 days. Spectroscopic analyses (UV–vis, XPS, ESR) and XRD measurements revealed atmosphere-dependent structural changes. In argon, hydrogen release generates Si dangling bonds, whereas in air the dangling bonds are terminated by oxygen-containing species. These findings clarify the hydrogen release mechanism of L-HSi.