Reversible H2 storage using a SAPO-34 zeolite layer

A SAPO-34 zeolite membrane was made essentially impermeable to high-pressure hydrogen at room temperature by adsorbing methanol in the SAPO-34 layer. Hydrogen permeance decreased three orders of magnitude when the methanol feed activity was ∼0.1, and it decreased more than six orders of magnitude when the methanol feed activity was higher than 0.85 at 293 K. The hydrogen permeance at 293 K was below ∼10−14 mol/m2 s Pa for at least five days for a H2 feed pressure of 6.6 MPa. At higher temperatures, methanol desorbed and the H2 flux increased. The hydrogen permeance could be controlled by the activity of the methanol on the feed side. These results demonstrate that the SAPO-34 membrane had low fluxes through defects, and H2 flow through these defects was blocked by capillary condensation of methanol at high methanol activities.