Complex pore spaces create record-breaking methane storage system for natural-gas vehicles

doi:10.1063/1.2786007It has been proposed that nearly space-filling networks of nanopores in biocarbon may provide a “sponge” for lowpressure, high-capacity storage of methane CH4 for advanced transportation.1 Such pores, a few molecular diameters wide, adsorb CH4 by strong van der Waals forces as a high- density fluid at low pressure and room temperature supercritical adsorption. The dense fluid arises because, in narrow pores, the tails of the substrate potential from opposite walls overlap and create a deep potential well. In the absence of nanopores, CH4 would just be a low-density gas. Maximum density of CH4 is predicted in pores of width 1.1 nm.This work has been supported by NSF (PFI-0438469), DOE (DE-AC02-06CH11357), DED (P200A040038), University of Missouri, Midwest Research Institute, and Kansas City Office of Environmental Quality (loan of test vehicle). We thank Nicolle Rager, NSF, for the superb graphic