Cascade Conversion of N ₂ , H ₂ O, and CO ₂ into NH ₄ HCO ₃ under Atmospheric Pressure

Ammonium bicarbonate (NH 4 HCO 3 ) is a widely used nitrogen fertilizer that simultaneously offers nitrogen and carbon while consuming CO 2 during its synthesis. Conventional NH 4 HCO 3 production relies on the Haber−Bosch process to generate NH 3 followed by CO 2 neutralization, resulting in high pressure operating conditions (400−500 °C, 100−200 bar). Herein, we present a cascade plasma-thermal catalytic route that converts N 2, H 2 O, and CO 2 into NH 4 HCO 3 under atmospheric pressure. In this process, non-thermal plasma activates N 2 and H 2 O to generate NO and H 2, bypassing thermodynamic constraints. The plasma-derived NO is then hydrogenated over Pt/HZSM-5 with supplementary H 2 from water electrolysis to produce NH 3 . Finally, simultaneous CO 2 absorption leads to the in situ formation of NH 4 HCO 3, achieving a yield rate of 114.5 mmol h –1 at a discharge current of 0.4 A. This integrated approach offers a pathway for nitrogen fertilizer synthesis from air and water, representing a step toward carbon−nitrogen cycle coupling.