Direct in situ NMR observation of lithium plating, corrosion, nitridation and protonolysis for ammonia synthesis

As a low-carbon and decentralized ammonia synthetic method, lithium-mediated electrochemical synthesis has shown promising efficiencies and reaction rates. Nevertheless, many mechanistic questions need to be addressed to optimize the process and in situ characterizations are in great need. Here we develop in situ NMR methodology that allows us to directly observe each reaction step of the catalytic cycle, including plating of metallic lithium and the concurrent corrosion, nitrogen splitting on lithium metal and protonolysis of lithium nitride. The in situ NMR methods are general and can be broadly applied for screening and understanding Li and beyond-Li catalysts for nitrogen splitting, accelerating the materials discovery for ammonia synthesis.