Radiocatalytic synthesis of ammonia under ambient conditions with efficiency exceeding that of Haber–Bosch process

Abstract Ammonia is an essential component to keep the world fed and fueled, but its industrial production through Haber–Bosch process requires high pressure and high temperature and is, therefore, energy- and emission-intensive. Few ammonia synthesis techniques have granted the capability to achieve comparable efficiency so far, even those that achieve comparable levels face substantial challenges in industrial scaling. Here, we reported that radiation-generated H atoms can activate the N≡N triple bond and enable NH3 conversion from water and nitrogen at room temperature and standard pressure. The water radiolysis with an electron-beam provided by a commercially available electron accelerator with the aid of a nanoscale metal–organic framework, i.e., Hf-UiO-66, achieves unprecedented NH3 yield rates of 48 μmol g−1 s−1. We attribute the high rate to promoted H atom generation associated with the reaction of hydrated electrons with an acid, the fragmentation of excited water, and the scavenging of symbiosis hydroxyl radical. Based on measured radiation-chemical yield around 0.06 μmol J−1, the energy efficiency is estimated to be approximately 17 MJ/mol NH3. The findings showed radiocatalysis NH3 synthesis can achieve conversions and rates that exceed those of the Haber–Bosch process. Owing to its operational simplicity and efficacy, H-atom-mediated radiation chemistry may provide a game-changing opportunity toward sustainable, decentralized, low-carbon NH3 production.