Carbon hydrogen oxygen energy storage

How much hydrogen can a carbon atom store?

Due to the combined effects of high surface area, high microporosity and an oxygen-rich nature, the carbons exhibit enhanced gravimetric hydrogen storage capacity of up to 8.1 wt% (total uptake) and 7.0 wt% (excess uptake) at −196 °C and 20 bar, rising to 8.9 wt% (total uptake) and 7.2 wt% (excess uptake) at 30 bar.

How do metal-doped carbons achieve enhanced hydrogen storage capacity?

The proposed mechanism by which metal-doped carbons achieve an enhanced hydrogen storage capacity is spillover, defined as ‘ the transport of an active species sorbed or formed on a first surface onto another surface that does not, under the conditions, adsorb or form the active species’.

What is a good binding energy for hydrogen storage?

For effective hydrogen storage via the spillover mechanism, C H binding energies need to be sufficiently high that the reaction 2 M e − C + H 2 → 2 M e − C − H proceeds thermodynamically downhill thus the C H binding energy must be > 1 / 2 E H 2 = ∼2.3 eV .

Are carbons useful as hydrogen storage materials?

To be useful as hydrogen storage materials, the carbons also need to exhibit a high level of porosity that mainly arises from micropores 7, 8, 9, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27. The porosity of the carbons was probed using nitrogen sorption analysis.

Are porous carbons a promising hydrogen storage material?

Hydrogen is attractive as a clean fuel for motor vehicles and porous carbons represent promising hydrogen storage materials. Here, Mokaya and colleagues incorporate oxygen-rich functional groups into porous carbons with high microporosity, showing that such materials exhibit significantly enhanced H2 storage capacity.

Does oxidation increase hydrogen storage capacity?

Wang et al. investigated the effect of oxidation of Pt-doped templated carbon and AX-21 activated carbon and reported increases in hydrogen storage capacities of 49% and 51% respectively over that of un-oxidised Pt-doped samples at 298 K and 100 bar .