Facile Preparation of Carbon Shells-Coated O-Doped Molybdenum Carbide Nanoparticles as High Selective Electrocatalysts for Nitrogen Reduction Reaction under Ambient Conditions

作者：Ximing Qu, Linfan Shen, Yujie Mao, Jin‐Xia Lin, Yuyang Li, Guang Li, Yuyang Zhang, Yanxia Jiang, Shi‐Gang Sun · 发表于：ACS Applied Materials & Interfaces · 年份：2019 · DOI：10.1021/acsami.9b09007 · 被引用次数：100 · 研究领域：Ammonia Synthesis and Nitrogen Reduction、Advanced Photocatalysis Techniques、Hydrogen Storage and Materials

Electrochemical nitrogen reduction reaction (NRR) has been considered as a promising alternative to the traditional Haber–Bosch process for the preparation of ammonia (NH 3 ) under ambient conditions. The development of cost-effective electrocatalysts with suppressive activity for hydrogen evolution reaction is critical for improving the efficiency of NRR. Herein, oxygen-containing molybdenum carbides (O-MoC) embedded in nitrogen-doped carbon layers (N-doped carbon) can be easily fabricated by pyrolyzing the chelate of dopamine and molybdate. A rate of NH 3 formation of 22.5 μg·h –1 ·mg cat –1 is obtained at −0.35 V versus reversible hydrogen electrode with a high faradaic efficiency of 25.1% in 0.1 mM HCl + 0.5 M Li 2 SO 4 . Notably, the synthesized O-MoC@NC-800 also exhibits high selectivity (no formation of hydrazine) and electrochemical stability. The moderate electron structure induced by the interaction between O-MoC and N-doped carbon shells can effectively weaken the activity of hydrogen evolution reaction and increase the faradaic efficiency of NRR. Additionally, by applying the in situ Fourier transform infrared spectroscopy, an associative reaction pathway is proposed on O-MoC@NC-800. This work provides new insights into the rational design of carbon-encapsulated metal nanoparticles as efficient catalysts for NRR at ambient conditions.