2020/07/21 by Dazhi Yao, Cheng Tang, Laiquan Li +5 · 2 citations
Chemical Engineering · Energy · #Advanced Photocatalysis Techniques #Ammonia Synthesis and Nitrogen Reduction #CO2 Reduction Techniques and Catalysts
paper · doi:10.1002/aenm.202001289
openalex publication_date 2020/07/21 · openalex created_date 2025/10/10 · openalex updated_date 2026/06/22
Abstract The electrochemical nitrogen reduction reaction (NRR) is a promising alternative to the energy‐intensive Haber–Bosch process for ammonia synthesis. Among the possible electrocatalysts, bismuth‐based materials have shown unique NRR properties due to their electronic structures and poor hydrogen evolution activity. However, identification of the active sites and reaction mechanism is still difficult due to structural and chemical changes under reaction potentials. Herein, in situ Raman spectroscopy, complemented by electron microscopy, is employed to investigate the structural and chemical transformation of the Bi species during the NRR. Nanorod‐like bismuth‐based metal–organic frameworks are reduced in situ and fragment into densely contacted Bi 0 nanoparticles under the applied potentials. The fragmented Bi 0 nanoparticles exhibit excellent NRR performance in both neutral and acidic electrolytes, with an ammonia yield of 3.25 ± 0 .08 µg cm −2 h −1 at −0.7 V versus reversible hydrogen electrode and a Faradaic efficiency of 12.11 ± 0.84% at −0.6 V in 0.10 m Na 2 SO 4 . Online differential electrochemical mass spectrometry detects the production of NH 3 and N 2 H 2 during NRR, suggesting a possible pathway through two‐step reduction and decomposition. This work highlights the importance of monitoring and optimizing the electronic and geometric structures of the electrocatalysts under NRR conditions.