I am curious about the fundamentals of metal hydrides and how adsorption/desorption works in non-hydrogen systems. My understanding is that the atom ratio M/Hx of the metal hydride is a function of the hydrogen partial pressure and temperature. For a metal hydride in a closed system with hydrogen I can understand this relationship. In this case, the partial pressure and total pressure would be equivalent. However, if the metal hydride was placed in a closed system with another gas, presumably inert, I am unsure what would occur and how you could quantify the system.
If we assume that the metal hydride is moved directly from the hydrogen closed-system to an inert gas closed-system with the same temperature and total pressure, then initially the hydrogen partial pressure in the inert gas system would be zero. Under these assumptions, are we able to determine evolution of the system or at least the equilibrium hydrogen partial pressure and total pressure that would be reached? If not, what other information or assumptions would be necessary?