Electron‐Deficient Mo2C Nanoclusters Embedded B, N Co‐Doped Hollow Carbon Fibers for Electrocatalytic Nitrate Reduction to Ammonia

Ammonia (NH₃) production from electrocatalytic nitrate reduction reaction (NO₃RR) is anticipated as a promising route to achieve both sustainable NH₃ generation and nitrate water pollution removal. Herein, the molybdenum carbide (Mo₂C) nanoclusters embedded in boron, nitrogen co-doped hollow carbon fibers (Mo₂C@BNHCFs) electrocatalyst is fabricated for NO₃RR by coaxial electrospinning and pyrolysis method. The uniformly dispersed Mo₂C nanoclusters and the B, N doped-carbon layer provide more adsorption sites for nitrate reduction, effectively improving the activity and long-term stability of Mo₂C@BNHCFs. Mo₂C@BNHCFs-2 achieves a maximum NH₃ yield of 6487.43 μg h^-1 mg_cat. ^-1 and Faradaic efficiency of 74.5% at -1.1 V (vs. reversible hydrogen electrode). Electrochemical in situ characterizations identify the formation of intermediates and products during the electrocatalytic NO₃ ^- reduction process. Meanwhile, theoretical calculations indicate that electrons transfer from Mo₂C nanoclusters to carbon supports can induce the creation of electron-deficient Mo₂C, thus effectively activating the NO₃ ^- and facilitating the electrochemistry process.