Industrial production of NH3 has been performed by the Haber-Bosch process for more than 100 years, in which dissociation of N2 feedstock molecules promoted by alkali atom co-catalyst is thought to be the rate limiting step. The Haber-Bosch synthesis consumes 1% of the world's total energy consumption, and accounts for 1.4% of the global CO2 emissions. Therefore, the atomic scale insights into the K atom-N2 molecule interactions on metal substrates and specifically, the alkali atom promotion chemistry, has global significance.