Theory of genus reduction in alkali-induced graphitization of nanoporous carbon

Exposure to elemental Cs generates graphitic domains within nanoporous carbon at only 50°C, well below the typical graphitization temperatures of >1000°C. We present a model of nanoporous carbon, the wormhole, which can express the fundamental topological elements of graphitization: a negative-curvature analog to C60 fullerene. The pathway to wormhole annihilation comprises an initial Stone-Wales transformation and a subsequent unzipping of the defect. This complex ∼100 -atom collective defect disintegrates with the formation of only two dangling bonds. Our ab initio calculations show that while the activation barrier against reduction in topological genus is indeed lowered by interaction with alkali, an additional chemical constituent must be involved to account for this remarkable local graphitization of nanoporous carbons at near-room temperature.