Electrocatalytic reduction of NO to NH3 in ionic liquids by P-doped TiO2 nanotubes

Designing advanced and cost-effective electro-catalytic system for nitric oxide (NO) reduction reaction (NORR) is vital for sustainable NH3 production and NO removal, yet it is a challenging task. Herein, it is shown that phosphorus (P)-doped titania (TiO2) nanotubes can be adopted as highly efficient catalyst for NORR. The catalyst demonstrates impressive performance in ionic liquid (IL)-based electrolyte with a remarkable high Faradaic efficiency of 89% and NH3 yield rate of 425 µg·h−1·mgcat.−1, being close to the best-reported results. Noteworthy, the obtained performance metrics are significantly larger than those for N2 reduction reaction. It also shows good durability with negligible activity decay even after 10 cycles. Theoretical simulations reveal that the introduction of P dopants tunes the electronic structure of Ti active sites, thereby enhancing the NO adsorption and facilitating the desorption of *NH3. Moreover, the utilization of IL further suppresses the competitive hydrogen evolution reaction. This study highlights the advantage of the catalyst—electrolyte engineering strategy for producing NH3 at a high efficiency and rate.