Catalytic effect of fullerene and formation of nanocomposites with complex hydrides: NaAlH 4 and LiAlH 4

Abstract

Carbonaceous nanomaterials utilized as scaffolds, catalysts, and additives in conjunction with complex metal hydrides have shown remarkable hydrogen sorption properties. Our studies have confirmed fullerene-C 60 is an excellent catalyst for temperature induced hydrogen desorption for both NaAlH 4 and LiAlH 4. Fullerene-containing complex metal hydride composites comprised of fullerene-C 60 with NaAlH 4 or LiAlH 4 desorbed hydrogen at elevated temperature and go onto form alkali metal fullerides and aluminum metal as final products. The as-prepared composites exhibit rapid hydrogen desorption at onset temperatures of 130 °C and 150 °C, and released hydrogen content of 5.9 and 2.2 wt.% (LiAlH 4 and NaAlH 4, respectively) relative to the composite. The resultant alkali metal fulleride containing composites have been characterized and are capable of reversible hydrogen storage. A series of desorption/absorption experiments on the Na–C 60 and Li–C 60 based composites demonstrate a 1.5 wt.% and a 1.2 wt.% reversible capacity, respectively. The complex metal hydride-C 60 systems were characterized by PCT, XRD, FT-IR, and TGA-RGA and demonstrate the formation of fulleride material similar to traditional hydrofullerenes which appear to be responsible for the observed reversible hydrogen storage.