Iron-Oxide Nanoarrays Covered Carbon Fiber Promotes Ammonia Electrosynthesis and Multi-Scenario Applications.

The development of electrocatalysts with complex environmental adaptability is the key path to promote the directional conversion of nitrate into high value-added ammonia. Herein, low-cost self-supporting carbon fiber was used as a carrier to successfully prepare uniform-sized Fe2O3 nanoarrays with four-corner double cone morphology (named Fe2O3/CF) through a one-step in situ growth method. Fe2O3/CF exhibits excellent performance in the electrocatalytic reduction of nitrate to ammonia: it maintains stable activity in a wide pH range and exhibits significant resistance to common interfering ions in complex water; The Faradaic efficiency of ammonia generation can reach 95%, and it has good long-term stability. The open-circuit voltage of 1.37 V and the power density of 12.3 mW cm-2 can be achieved in the Zn-NO3 - battery system based on Fe2O3/CF. Ammonia synthesis with low carbon emission and continuous production of liquid nitrogen fertilizer are realized by using solar power generation module. Combined with non-thermal plasma air activation technology, the green stepwise conversion of "air-nitrogen oxides-ammonia" can also be efficiently completed. Experiments and theoretical demonstrate that the Fe2O3 nanoarray uniformly dispersed on the surface of carbon fibers enables efficient and highly selective reduction of nitrate to ammonia by exposing specific crystal planes and providing high-density active sites.