Tribo-Electro-Catalytic Nitrogen Fixation Directly from Natural Air Through BaTiO <sub>3</sub> Nanofibers Harvesting Friction Energy

The ambient friction energy can be triboelectrically harvested to convert into the electric energy and can drive some chemical reaction, which can be named tribo-electro-catalysis. In atmosphere, about 78% of the natural air is nitrogen (N2). In this work, the excellent tribo-electro-catalytic N2 fixation driven via friction has been achieved in barium titanate (BaTiO3) nanofibers which is synthesized via the two-step hydrothermal method. BaTiO3 nanofibers harvest the friction energy from stirring, driving the tribo-electro-catalytic N2 reduction directly from natural air at room temperature. After 10 h stirring in dark, the ammonia radical (NH4+) production rate is up to about 215.1 μmol·L-1·g-1·h-1 with methanol as the positive charges scavenger. Meanwhile, NH4+ does not generate without catalyst or contact between the stirring rod and catalyst. Furthermore, it is also found that the tribo-electro-catalytic N2 fixation performance is strongly correlated to the pH of the reaction solution, the friction force and contact area between the stirring rod and catalyst. This excellent and efficient tribo-electro-catalysis can provide a potential avenue towards harvesting friction energy for the nitrogen fixation from the natural air.