Recently, a new record for the electrochemical reduction of N2 into NH3 production under ambient conditions was set. Such an achievement was made corporately by Professor ZENG Jie at USTC and Professor SI Rui at Shanghai Institute of Applied Physics, Chinese Academy of Sciences.
The research article was published in Advanced Materials entitled Achieving a Record-High Yield Rate of 120.9 μgNH3 mg-1cat. h-1 for N2 Electrochemical Reduction over Ru Single-atom Catalysts.
Given that Haber-Bosch process, a conventional way to synthesize ammonia by transforming N2 and H2 gases into NH3 on the surface of Fe or Ru-based heterogeneous catalysts under high pressure (150-350 atm) and temperature (350-550 ℃), is power consuming and environment unfriendly, scientists are looking for new methods that can reduce N2 into NH3. In this case, N2 electrochemical reduction demonstrates great advantages. On the one hand, this reaction can be carried out under ambient conditions. On the other hand, the energy is supplied by solar and other sources of renewable electricity and the large quantities of hydrogen source can be derived from water.

Scheme of the synthetic procedure for Ru single atoms distributed on nitrogen‐doped carbon. (Image from GENG Zhigang)
The key of the whole process is the synthesis of highly dispersed Ru single atom. After a great deal of experiments, researchers found an ideal way to prepare Ru single atom via pyrolyzing the Ru-containing derivative of zeolitic imidazolate frameworks (ZIF-8). After improvement and optimization, the yield rate of Ru SAs/N-C reaches 120.9μgNH3mg-1cat. h-1, which is one order of magnitude higher than the highest value ever reported. This work not only develops a superior electrocatalyst for NH3 production, but also provides a guideline for the rational design of highly active and robust single-atom catalysts.
This work was supported by Collaborative Innovation Center of Suzhou Nano Science and Technology, MOST of China, NSFC, Key Research Program of Frontier Sciences of the CAS, Anhui Provincial Key Scientific and Technological Project, Major Program of Development Foundation of Hefei Center for Physical Science and Technology and Fundamental Research Funds for the Central Universities.
(Written by HU Xiaowen, edited by WU Qiran, USTC News Center)