Direct Conversion of N2 to Nitric Acid via Contact Electrocatalysis

Nitric acid (HNO3) as a vital chemical is widely used in energy and environmental fields. However, its conventional production relies on ammonia synthesis, resulting in high energy consumption and environmental concerns. Here, we report a simple, efficient, and green conversion of N2 to HNO3 by contact electrocatalysis (CEC) under ambient conditions. Utilizing the electrification of poly(tetrafluoroethylene) (PTFE) particles with water under ultrasound, we demonstrate how this interaction promotes the activation of N2. Our results showed that the average yield of HNO3 can reach 40.73 ± 1.80 μM h–1 in air gas atmosphere. We utilized electron spin resonance and the fluorescence spectrum to confirm the evolution of hydroxyl radicals (·OH). High-resolution mass spectrometry combined with isotope experiments provides strong evidence that water-PTFE can produce a contact electric effect through ultrasonic treatment, directly oxidize water or reduce O2 to produce ·OH, and oxidize N2 to produce HNO3 under anaerobic or aerobic conditions. This work not only provides a green and efficient method for direct N2 fixation into HNO3 but also stimulates further exploration of CEC-driven chemical processes, particularly highlighting its potential for industrial application, and attempts to explain some of the N2 fixation phenomena in the environment.