Ammonia (NH3) is a fundamental feedstock for the global population not only for its wide use as fertilizer and chemical, but also for its potential as energy storage medium. Its synthesis at the industrial scale is based on the well-known Haber Bosch process, operating at high temperature (400-500°C) and high pressure (150-300atm), thus making it highly pollutant. Considering the global climate emergency, it is mandatory to develop a green ammonia synthesis that relies on milder conditions and may adopt renewable energy sources. The electrochemical synthesis, of NH3 from N2 and H2O at ambient conditions and using renewable energy driven electricity could be a promising approach. An efficient electrochemical ammonia synthesis however, is currently still lacking. The main reasons are the absence of adequate catalysts capable of dissociating the N2 triple bond and the competition with the hydrogen …