Methane Storage in Nanoporous Carbons

Global warming is a problem of increasing concern to present society. There are important efforts to found solutions, especially to reduce the urban pollution, which implies mainly to reduce emissions from road transport vehicles. Natural gas is an efficient and sustainable alternative to traditional fuels, such as gasoline and diesel. Natural gas-powered vehicles reduce the CO2 emissions between 15 and 25% and the NOx emissions an 80% and practically does not emit solid pollutant particles and SOx. These vehicles reduce the cost of covering one kilometer a 35% and 50% with respect to the diesel and gasoline vehicles, respectively. Most of the natural gas vehicles are compressed natural gas vehicles, at high pressures, or liquefied natural gas vehicles, which require very low temperatures. A recent type of gas vehicle is the adsorbed natural gas vehicle, where the gas is stored by adsorption on porous solids at moderate pressures and ambient temperature. Nanoporous carbons are the only type of porous solid used nowadays in prototypes and commercial adsorbed natural gas tanks and vehicles, due to their high methane storage capacities and cheap price. Many research efforts are oriented towards maximizing the methane storage capacities of nanoporous carbons, which implies a knowledge of their structural and methane adsorption properties