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Hydrogen fuel cells are a very promising potential replacement for internal combustion engines. However, their current use is limited by carbon monoxide poisoning of the platinum anode catalyst that occurs when CO enters the cell in the H2 feed gas. A novel new solution to this problem is the addition of a metal/graphene filter membrane exterior to the cell. This membrane will remove CO from the feed gas, allowing reduced loading of the expensive Pt catalyst and increasing cell lifetime. In the current work, density functional theory (DFT) was used to analyze graphene membranes containing nickel, copper, platinum, and iridium/gold atoms. The binding energy of the metal to the graphene was measured for a lone system and in the presence of CO and H2 to predict its durability. The binding energy of CO and H2 to metal was also measured to estimate its efficiency. All systems were analyzed using natural bond orbitals (NBOs). It was found that copper is a poor choice for use in membranes in all respects. Nickel systems show the most promise: they have a consistent metal/graphene binding energy when feed gas molecules are introduced. In addition, although CO binding is strong to Ni, Pt, and Ir/Au, nickel systems show the weakest interaction with H2. NBO analysis of these systems shows that metal orbitals are the most involved in bonding.

General rightsThis document is made available in accordance with publisher policies. Please cite only the published version using the reference above. Full terms of use are available: http://www.bristol.ac.uk/pure/about/ebr-terms The study mainly focuses on H2 stored within the fullerene with some investigation into external H2. A significant attractive Cfullerene-H2 interaction energy of -28 kJ/mol is observed for H2 in curved carbon nanomaterials where H2 molecules are located ca. 2.9 Å from carbon atoms in a highly confined system. Dopants have the potential to increase the favourability of Cfullerene-H2interactions when multiple H2 molecules are present by affecting the orientation of H2 molecules within the carbon nanomaterial. This paper presents analysis of several carbon nanosystems and then proposes possible materials for H2 storage on board vehicles.2

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