Durable Electrocatalytic Reduction of Nitrate to Ammonia over Defective Pseudobrookite Fe 2 TiO 5 Nanofibers with Abundant Oxygen Vacancies.

We propose the pseudobrookite Fe TiO nanofiber with abundant oxygen vacancies as a new electrocatalyst to ambiently reduce nitrate to ammonia. Such catalyst achieves a large NH yield of 0.73 mmol h  mg and a high Faradaic Efficiency (FE) of 87.6 % in phosphate buffer saline solution with 0.1 M NaNO , which is lifted to 1.36 mmol h  mg and 96.06 % at -0.9 V vs. RHE for nitrite conversion to ammonia in 0.1 M NaNO . It also shows excellent electrochemical durability and structural stability. Theoretical calculation reveals the enhanced conductivity of this catalyst and an extremely low free energy of -0.28 eV for nitrate adsorption at the presence of vacant oxygen.