Hydrogen gas is a potential fuel to replace gasoline on board vehicles. However, viable storage methods must be developed. Carbon nanomaterials are promising because they are cheap, lightweight and abundant but carbon-hydrogen physisorption is weak and chemisorption interactions are undesirable. The present project investigates methods of strengthening C-H2 physisorption without introducing chemisorption by activation of carbon nanomaterials using curvature. Confinement and doping are also examined (results not shown). Fullerenes of varying size with different degrees of curvature (Cn, n = 20, 60, 180, 540, 960) were investigated. Favourable physisorption was observed with H2 placed in C60 and C180 where H2 was in a position that allowed interaction with many carbon atoms. In contrast, H2 in C20 showed strong repulsive C-H2 interactions and H2 in C540 and C960 (large fullerenes with flat sides) experienced negligible interaction. This suggests that hydrogen can be stored in carbon nanomaterials only when the curvature allows H2 to interact with many carbon atoms and the C-H2 distance is desirable. Upon optimization of these conditions, carbon nanomaterials have potential for H2 storage. This will allow hydrogen to be stored safely and cheaply on board fuel cell vehicles.
Journal: TechConnect Briefs
Volume: Technical Proceedings of the 2014 Clean Technology Conference and Trade Show
Published: June 15, 2014
Pages: 147 - 150
Industry sector: Energy & Sustainability
Topics: Fuel cells & Hydrogen