In recent years, as a strategy for activating nitrogen under ambient conditions, electrochemical reduction of nitrogen to ammonia has shown great potential. To realize efficient electrochemical nitrogen fixation，scientists have been trying to design a reasonable electrocatalyst with the optimal nitrogen adsorption and activation capability.

A recent research, led by Prof. ZHANG Haimin from Institute of Solid State Physics, Hefei Institutes of Physical Science (HFIPS), successfully realized the synthesis of Mo single atoms anchored on activated carbon (Mo-SAs/AC) by the formed Mo-Ox bonds. The result was published on Chemical Communications.

This new oxygen-coordinated molybdenum single atom catalyst was proved efficient to electrosynthesis of ammonia. The O-coordinated environment in this study, different from N-coordinated environment reported before, provided the sites to anchor Mo single atoms and form Mo–Ox sites, which could be used as the active centers for the adsorption and activation of N₂, resulting in high nitrogen reduction reaction (NRR) activity.

"We have been curious about the key to the high NRR catalytic activity,” said GENG Jing, the first author of the paper, “then we found the Mo-Ox site in the catalyst.”

In this research, the surface-rich oxygen functional groups of pre-treated activated carbon played an important role in capturing the Mo precursor, forming Mo-O coordination to anchor Mo atoms as the catalytic active sites.

As a result, in 0.1 M Na₂SO₄ electrolyte, the Mo-SAs/AC can produce 2.55±0.31 mg of NH3 per hour and attain a faradaic efficiency of 57.54±6.98% at -0.40 V (vs. RHE) with high stability and good durability.

This work would be very helpful for designing and developing oxygen-coordinated single atom NRR electrocatalysts for high efficiency electrosynthesis of ammonia.

This work was financially supported by the National Key R&D Program of China (2017YFA0207202), the Natural Science Foundation of China (Grant No. 51872292), the China Postdoctoral Science Foundation (Grant No. E04BFGCV), and the HFIPS Director’s Fund (Grant No. YZJJ2021QN18).

Link to paper: An oxygen-coordinated molybdenum single atom catalyst for efficient electrosynthesis of ammonia

Schematic illustration of the synthetic process of Mo-SAs/AC. (Image by GENG Jing)

Contact:

ZHAO Weiwei
Hefei Institutes of Physical Science (http://english.hf.cas.cn/)
Email: annyzhao@ipp.ac.cn