After separation of the produced NH3, usually achieved by condensation, the remaining reactants are recycled with part of the recycle stream being purged to avoid the accumulation of impurities like argon (Ar) or methane (CH4) in the process. Both the thermodynamically induced low conversion and the resulting substantial need for reactant recycling and purging can be tackled by the process intensification strategy of sorption enhancement. In this approach, also referred to as in situ separation, the product NH3 is selectively removed from the gas phase by a sorbent material. Since the equilibrium limitation is no longer given, sorption-enhanced NH3 synthesis (SEAS) has the potential to enable higher or even near full conversion and thus to make do without recycling and purging. In contrast, ex situ separation describes the removal of NH3 from the gas phase downstream of the reactor. Note that in this study, the term "sorption" is used to describe either "absorption" or "adsorption". The difference between both terms as used in the context of NH3 sorption is explained in detail by Smith et al. Sorptive separation of NH3 can be achieved with different solid materials. One important class that also allows for NH3 sorption at elevated temperatures are metal halide salts. Multiple studies have been conducted on ex situ NH3 separation most commonly applying MgCl2 or CaCl2 9,14-17 , both in bulk form or impregnated onto a support material like silica (SiO2) or alumina (Al2O3) . In literature, the NH3 sorption capacity of metal halides is typically described in two different ways: The first and more commonly applied method is based on the so-called equilibrium pressure, which is calculated with the Van't Hoff equation and represents the NH3 partial pressure required in the gas phase for any sorption to take place. However, it has been observed during breakthrough experiments at elevated temperature that before saturation of the sorbent, the NH3 partial pressure in the gas phase is significantly lower than the theoretical equilibrium pressure and actually approaches 0, particularly when supported metal halides are applied. The second method of describing the NH3 sorption capacity considers this phenomenon and applies e.g. Langmuir-type isotherms to describe the equilibrium sorbent capacity depending on the NH3 partial pressure. One important difference is that in the latter approach, the sorbent capacity changes continuously with the NH3 partial pressure, while the former approach sees the equilibrium pressure as cut-off criterion for NH3 sorption regardless of the current sorbent loading. Other than by metal halides, NH3 can also by removed by porous solid materials like zeolites , MOFs 10 , SiO2 or activated carbon (AC) .