Ruthenium doping: An effective strategy for boosting nitrite electroreduction to ammonia over titanium dioxide nanoribbon array

Electrochemical reduction of nitrite (NO2–) not only removes NO2– contaminant but also produces high-added value ammonia (NH3). This process, however, needs efficient and selective catalysts for NO2−-to-NH3 conversion. In this study, Ruthenium doped titanium dioxide nanoribbon array supported on Ti plate (Ru–TiO2/TP) is proposed as an efficient electrocatalyst for the reduction of NO2− to NH3. When operated in 0.1 M NaOH containing NO2–, such Ru–TiO2/TP achieves an ultra-large NH3 yield of 1.56 mmol h−1 cm−2 and a super-high Faradaic efficiency of 98.9%, superior to its TiO2/TP counterpart (0.46 mmol h−1 cm−2, 74.1%). Furthermore, the reaction mechanism is studied by theoretical calculation.