An Electrochemical Haber-Bosch Process

Ammonia, produced via the Haber-Bosch (HB) process, is globally the leading chemical in energy consumption and carbon dioxide emissions. In ammonia plants, hydrogen is generated by steam-methane reforming (SMR) and watergas shift (WGS) and, subsequently, is purified for the high-pressure ammonia synthesis. Herein, we demonstrate how these steps are integrated into a single BaZrO3-based protonic ceramic membrane reactor (PCMR), operating at atmospheric pressure. Hydrogen generation occurs on a Ni-composite electrode, while VN-Fe is the ammonia synthesis electrocatalyst. Hydrogen extraction from the reforming compartment enhances the thermodynamically limited methane conversions, whereas 5%-14% of the pumped protons are converted to ammonia. An electrochemical HB is designed by combining this PCMR with a protonic ceramic fuel cell to recover electricity and separate nitrogen from ambient air by exploiting by-product hydrogen. This process could potentially require less energy and release less carbon dioxide emissions than its conventional counterpart, holding promise for sustainable decentralized applications.