Efficient and Stable Ammonia Synthesis from Ambient Air and Water via Integrated Plasma‐Electrocatalytic Process

Electricity driven nitrogen (N 2 ) reduction (eNRR) presents one green and ambient alternative to Haber–Bosch ammonia (NH 3 ) synthesis. However, NH 3 yield rate and selectivity are extremely low due to failures in sufficient N 2 activation and suppressing robust competitive reaction. Herein, efficient plasma N 2 activation is matched with thermodynamically favorable electrocatalytic hydrogenation in the specially integrated system and achieves sustainable and ambient NH 3 synthesis directly using air and water. Through this well‐designed reactor with an optimal Cu mesh electrode, high NH 3 Faradaic efficiency of 91.42% and yield rate of 14.01 mg h −1 cm −2 are achieved, largely surpassing eNRR and sole nitrite (NO 2 − ) electroreduction in a similar electrolyte. Using in situ experiments and theoretical calculations, it is found that NH 3 synthesis mainly goes through plasma N 2 oxidation into gaseous nitric oxide (NO) and aqueous NO 2 − , followed by the electroreduction of these intermediates to NH 3 . The slightly oxidized Cu species with low coordination state and high NO affinity, which are stabilized by plasma treatment, account for the accelerated reaction kinetics of * NO hydrogenation and the suppressed combination of * H into hydrogen. This work highlights the possibility of sustainable NH 3 synthesis directly from ambient air and water beyond the fossil fuel‐driven synthesis process.