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 water-gas 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. [Display omitted] •Combination of H2 production and purification with NH3 synthesis in a single cell•Up to 14% NH3 faradaic efficiency by employing a VN-Fe electrocatalyst•Enhanced CH4 conversion to CO2 upon H2 extraction from the reforming chamber•An electrochemical Haber-Bosch can produce NH3 with less energy and CO2 emissions Ammonia is a key chemical for the fertilizer industry and also a potential clean energy carrier for the future. Ammonia, produced via the Haber-Bosch process, is the most energy-intensive commodity chemical, responsible for 1%–2% of global energy consumption and 1.44% of CO2 emissions. Here, we employ a protonic ceramic membrane reactor to incorporate the essential stages of the conventional plant in a single device, including ammonia synthesis, steam-methane reforming, water-gas shift, and hydrogen purification. This capability of the proposed cell allows notable conversions under milder conditions than a typical ammonia plant. By integrating the proposed reactor with a protonic ceramic fuel cell to exploit the hydrogen residual, we design an electrochemical alternative to conventional HB plants. This new strategy can lead to up to 4 times less energy consumption, with 50% lower emissions than its conventional counterpart, holding promise for sustainable decentralized applications. Ammonia is the primary chemical intermediate