Laser-Induced Nitrogen Fixation

Industrial ammonia production is currently performed at 400–500 °C and 100–200 bar with fossil–fuel–involved power and hydrogen feedstock by the Haber-Bosch method, which enabled the growth of humanity beyond previous limits but demands larger infrastructure, capital investments and causes substantial emissions of carbon dioxide. For distributed ammonia production and decarbonization of this process by exploiting renewable energy sources, alternative methods, such as the electrochemical approach or using plasma on a small–scale, have been explored. Nonetheless, they still lack yield and efficiency to be industrially relevant. Here, we demonstrate a new approach of nitrogen fixation to synthesize ammonia at ambient conditions via laser–induced multiphoton dissociation of lithium oxide. Lithium oxide is dissociated under non–equilibrium multiphoton absorption and high temperatures under focused infrared light, and the generated zero–valent metal spontaneously fixes nitrogen and forms a lithium nitride, which upon subsequent hydrolysis generates ammonia. The highest ammonia yield rate of 30.9 micromoles per second per square centimeter is achieved at 25 °C and 1.0 bar nitrogen. This is two orders of magnitude higher than state–of–the–art ammonia synthesis at ambient conditions. The focused infrared light here is produced by a commercial simple CO2 laser, serving as a demonstration of potentially solar pumped lasers for nitrogen fixation and other high excitation chemistry. We anticipate such solar-laser-involved technology will bring unprecedented opportunities to realize not only local ammonia production but also other new chemistry

Laser-induced nitrogen fixation

Abstract For decarbonization of ammonia production in industry, alternative methods by exploiting renewable energy sources have recently been explored. Nonetheless, they still lack yield and efficiency to be industrially relevant. Here, we demonstrate an advanced approach of nitrogen fixation to synthesize ammonia at ambient conditions via laser–induced multiphoton dissociation of lithium oxide. Lithium oxide is dissociated under non–equilibrium multiphoton absorption and high temperatures under focused infrared light, and the generated zero–valent metal spontaneously fixes nitrogen and forms a lithium nitride, which upon subsequent hydrolysis generates ammonia. The highest ammonia yield rate of 30.9 micromoles per second per square centimeter is achieved at 25 °C and 1.0 bar nitrogen. This is two orders of magnitude higher than state–of–the–art ammonia synthesis at ambient conditions. The focused infrared light here is produced by a commercial simple CO2 laser, serving as a demonstration of potentially solar pumped lasers for nitrogen fixation and other high excitation chemistry. We anticipate such laser-involved technology will bring unprecedented opportunities to realize not only local ammonia production but also other new chemistries

Flexible N‑Doped Graphene Electrodes Fabricated via Rapid Direct Hot Stamping for Microsupercapacitors

Motivated by the advancements in portable and wearable electronics, the rising necessity for microscale energy storage electronics has prompted extensive research on the efficient and cost-effective preparation of high-performance electrode materials. Herein, a facile fabrication method of N-doped graphene-based electrodes is demonstrated for in-plane microsupercapacitors (MSCs) on flexible textile. Our approach involves a one-step direct hot stamping of 10 s for efficient reduction of graphene oxide (GO) and simultaneously N doping into reduced GO (N-rGO). The degree of N doping is controlled by varying the concentrations of precursor chitosan (CS) in GO. Benefiting from the enhanced N doping, the N-rGO 15% electrodes prepared with a CS-to-GO mass ratio of 0.15 exhibit excellent volumetric capacitance of 42.2 F cm–3, exceptional energy density of 3.01 mWh cm–3, and a maximum power density of 31.57 mW cm–3, along with the outstanding mechanical flexibility and cycle stability. Besides, serial integration of the MSCs interwoven on short sleeves was also performed to light a customized LED, suggesting its potential as a power source in wearable devices. Therefore, the proposed hot stamping strategy offers insights for the development of an integrated and multifunctional textile