Effects of electric potential on hydrogen adsorption

Hydrogen adsorption isotherms of activated carbon and its mixture with platinum coated activated carbon under various electric potentials and hydrogen pressures were measured at ambient temperature. Results indicated that electric potential enhanced hydrogen adsorption. The higher the applied electric potential is, the higher the hydrogen adsorption capacity is in the experimental range of 0-3000 V. The total amount of hydrogen adsorption increases with the hydrogen pressure. However, the enhancement is more obvious at hydrogen pressures below 10 bars. The enhancement ratio can reach about 160% at 1.6 bars pressure and 3000 V applied electric potential, but decreases to about 20% at 80 bars pressure under the same voltage. The adsorption enhancement is much more significant for the mixture of platinum coated activated carbon and activated carbon at a ratio of 1-4. At 1.6 bars, the hydrogen adsorption capacity increases from 0.008 wt.% at 0 V to 0.058 wt.% at 2500 V, which is a 625% adsorption enhancement. At 83 bars, the hydrogen adsorption capacity increases from 0.43 wt.% at 0 V to 0.56 wt.% at 2500 V, about 30% adsorption enhancement.