Development of exfoliated layered stannosilicate for hydrogen adsorption

• A new layered stannosilicate UZAR-S3 (Na4SnSi5O14·3.5H2O) is synthesized.
• UZAR-S3 is delaminated producing UZAR-S4.
• UZAR-S4 is composed of sheets a few nanometers thick with surface area of 236 m2/g.
• At −196 °C for UZAR-S4, H2 adsorption reach values of 4.2 wt% for 40 bar.

The use of hydrogen as an energy vector leads to the development of materials with high hydrogen adsorption capacity. In this work, a new layered stannosilicate, UZAR-S3, is synthesized and delaminated, producing UZAR-S4. UZAR-S3, with the empirical formula Na4SnSi5O14·3.5H2O and lamellar morphology, is a layered stannosilicate built from SnO6 and SiO4 polyhedra. The delamination process used here comprises three stages: protonation with acetic acid, swelling with nonylamine and the delamination itself with an HCl/H2O/ethanol solution. UZAR-S4 is composed of sheets a few nanometers thick with a high aspect ratio and a surface area of 236 m2/g, twenty times higher than that of UZAR-S3. At −196 °C for UZAR-S4, H2 adsorption reached remarkable values of 3.7 and 4.2 wt% for 10 and 40 bar, respectively, the latter value giving a high volumetric H2 storage capacity of 26.2 g of H2/L.

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