Ambient ammonia production via electrocatalytic nitrite reduction over MoO2 nanoparticles self-supported on molybdenum plate

Electrocatalytic reduction of nitrite (NO2–) is an environmentally friendly method for ambient ammonia (NH3) production, and the development of high–efficiency electrocatalysts is in urgent demand. Herein, we demonstrated that MoO2 nanoparticles self–supported on a molybdenum plate (MoO2/MP) could act as an excellent catalyst for the conversion of NO2– to NH3. The optimized catalyst can achieve an impressive NH3 yield of 8678.4 ± 187.4 μg h–1 cm–2 with high Faradaic efficiency of 94.5 ± 0.2 % at −0.8 V in the solution of 0.5 M Na2SO4 and 0.1 M NO2–, along with preferable durability. Additionally, density functional theory calculation reveals that the MoO2 (1¯11) surface has a high activity for NO2– reduction, with 0.38 eV as the potential determining step (*NO2 to NO2H), as well as severe suppress hydrogen evolution.