After a century of status quo in the Haber-Bosch process for synthesizing ammonia, the prospect for green ammonia derived from renewable energy has reinvigorated the development of novel catalysts, but a holistic approach considering both reaction and separation is required. Lower operating pressures—the principal target for process innovations—are constrained by the thermodynamic and practical limitations imposed by the reaction equilibrium and separation characteristics. Both conventional condensation separation and emerging technologies, such as absorption display, lower limits on the operating pressure of the catalyst. As such, the separation techniques should guide the targeting of catalyst design for moderate pressures (10–30 bar) as opposed to atmospheric pressures prevalent in the literature. Under such conditions, removing hydrogen and ammonia inhibition becomes crucial. In describing the constraints imposed by process design, this work provides direction for the development of catalysts for green ammonia production as both a fertilizer and a renewable energy vector.