Boosting Electrocatalytic Nitrite Reduction to Ammonia in Neutral Media by MoSe2 Nanosheet with Se Vacancies

Electrocatalytic reduction of nitrite (NO2−RR) is considered an effective method for removing harmful NO2− in wastewater while simultaneously generating high-value-added ammonia (NH3). This process, however, requires electrocatalysts with high activity and selectivity. Herein, a MoSe2 nanosheet array with Se vacancies supported on carbon cloth (MoSe2– x/CC)is proposed as a high-efficiency electrocatalyst for NO2− reduction to NH3. In 0.1 M phosphate-buffered saline with 0.1 M NO2−, MoSe2–x/CC exhibits an outstanding NH3 yield of 446.0 μmol h−1 cm−2 and a Faradaic efficiency of 96.9%, overpassing that of MoSe2/CC (278.1 μmol h−1 cm−2, 83.1%). Additionally, density functional theory calculations gain insights into reaction mechanism of MoSe2–x towards NO2−RR.