The progress of electrochemical ammonia synthesis

In electrolysis, II is not only an electric active species, but also provides protons required for the reaction. Pichett described the probability of ammonia synthesis in small-scale industrialization by this principle. In his method, the protonation was realized by adding TSOH H2O. It did not form a real cycle and they did not report the reaction and material of positive electrode as well as the rates of ammonia formation. 

In 1987, Tames et al. at Ben-Curion University (Israel) found that the reduction of Cp2TiCl2 at constant electric potential in the presence of N2 and catechol led to 

6 Schematic diagram of electrochemicai ammonia synthesis cycle 

The above ammonia synthesis processes take place in nonaqueous solution. Their chemical environment is very different from that of biological nitrogen fixation. They are not true electrochemical ammonia synthesis because the electrochemical method is used for regeneration of precursor of complex only. 

In 1989, Huruyanagai and Kichihaneshou at University of Yamanashi reported an electrochemical ammonia synthesis method at normal temperature and atmospheric pressure in aqueous solution.The gas diffusion electrode supported Fe-Phthalocyanine catalyst was used and the experimental instrument was shown in Fig. 10.7.  

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