Beyond Haber-Bosch: The renaissance of the Claude process

Ammonia may be one of the energy carriers in the hydrogen economy. Although research has mostly focused on electrochemical ammonia synthesis, this however remains a scientific challenge. In the current article, we discuss the feasibility of single-pass thermochemical ammonia synthesis as an alternative to the high-temperature, high-pressure Haber-Bosch synthesis loop. We provide an overview of recently developed low temperature ammonia synthesis catalysts, as well as an overview of solid ammonia sorbents. We show that the low temperature, low pressure single-pass ammonia synthesis process can produce ammonia at a lower cost than the Haber-Bosch synthesis loop for small-scale ammonia synthesis (<40 t-NH3 d−1).