Enhanced room-temperature hydrogen storage in super-activated carbons: The role of porosity development by activation

摘要

Efficient hydrogen storage with a high density under near-ambient temperature remains a key technical obstacle for a hydrogen economy. Here we demonstrate the enhanced room-temperature hydrogen storage in super-activated carbon materials, which were prepared by carbon dioxide activation of tem-plated porous carbons. These carbon materials possess high specific surface areas of up to 2829 m~2/g, large pore volumes of up to 2.34 cm~3/g, and hierarchical pore structures consisting of primary micro-pores with median size in the range of 0.7-1.3 nm and secondary mesopores with the size of 2-4 nm. One of the super-activated carbons exhibits a high hydrogen uptake of 0.95 wt% at 298 K and 80 bar, which is among the highest data reported for the porous carbon materials at room temperature and moderate pressure. The role of porosity development caused by activation in improving the hydrogen storage properties of the carbon materials has been investigated. A close relationship between hydrogen storage capacities and micropore volumes has been found. The microporosity development, especially the rapid increase of narrow pores with the diameters around 1.2 nm, appears to be essential for the enhanced room-temperature hydrogen storage in the super-activated carbons.