We predict by using molecular simulation that a novel class of carbonaceous materials called graphitic carbon inverse opal (GCIO) provides an excellent absorbent for hydrogen storage at room temperature. Simulation results based on well-calibrated force fields show that the gravimetric delivery amount of hydrogen at T = 298 K and p = 30.25 MPa achieves up to 5.9 wt % when the diameter of the spherical cavity in the GCIO materials is 1.78 nm. The corresponding volumetric delivery capacity of hydrogen reaches up to 50 kg/m(3), very close to the target set by the Department of Energy (DOE). A major advantage of the GCIO materials is that their mass-production is technically accessible, which makes them a good candidate for inexpensive storage of hydrogen in future automobile vehicles.