Electron-Deficient MoC Nanoclusters Embedded B, N Co-Doped Hollow Carbon Fibers for Electrocatalytic Nitrate Reduction to Ammonia.

Ammonia (NH) production from electrocatalytic nitrate reduction reaction (NORR) is anticipated as a promising route to achieve both sustainable NH generation and nitrate water pollution removal. Herein, the molybdenum carbide (MoC) nanoclusters embedded in boron, nitrogen co-doped hollow carbon fibers (MoC@BNHCFs) electrocatalyst is fabricated for NORR by coaxial electrospinning and pyrolysis method. The uniformly dispersed MoC nanoclusters and the B, N doped-carbon layer provide more adsorption sites for nitrate reduction, effectively improving the activity and long-term stability of MoC@BNHCFs. MoC@BNHCFs-2 achieves a maximum NH yield of 6487.43 μg h mg 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 NO reduction process. Meanwhile, theoretical calculations indicate that electrons transfer from MoC nanoclusters to carbon supports can induce the creation of electron-deficient MoC, thus effectively activating the NO and facilitating the electrochemistry process.