Boosted Electrocatalytic N₂ Reduction to NH₃ by Defect‐Rich MoS₂ Nanoflower

The industrial artificial fixation of atmospheric N 2 to NH 3 is carried out using the Haber–Bosch process that is not only energy‐intensive but emits large amounts of greenhouse gas. Electrochemical reduction offers an environmentally benign and sustainable alternative for NH 3 synthesis. Although Mo‐dependent nitrogenases and molecular complexes effectively catalyze the N 2 fixation at ambient conditions, the development of a Mo‐based nanocatalyst for highly performance electrochemical N 2 fixation still remains a key challenge. Here, greatly boosted electrocatalytic N 2 reduction to NH 3 with excellent selectivity by defect‐rich MoS 2 nanoflowers is reported. In 0.1 m Na 2 SO 4 , this catalyst attains a high Faradic efficiency of 8.34% and a high NH 3 yield of 29.28 µg h −1 mg −1 cat. at − 0.40 V versus reversible hydrogen electrode, much larger than those of defect‐free counterpart (2.18% and 13.41 µg h −1 mg −1 cat. ), with strong electrochemical stability. Density functional theory calculations show that the potential determining step has a lower energy barrier (0.60 eV) for defect‐rich catalyst than that of defect‐free one (0.68 eV).