Computational Predictions of Catalytic Activity of Zincblende (110) Surfaces of Metal Nitrides for Electrochemical Ammonia Synthesis

Here we present comprehensive results of theoretical analyses conducted with density functional theory on the (110) texture orientations of the zincblende structures of 23 transition metal nitrides to explore new candidates for catalyzing N 2 electroreduction reaction (NER) at ambient conditions. The catalytic activity of these surfaces is investigated by constructing the free energy diagrams via the Mars–van Krevelen mechanism. The stability of these materials against poisoning in electrochemical media and decomposition to parental metals under operational conditions is scrutinized. The catalyst regeneration rate is compared with the rate of decomposition in order to explore the sustainability of the catalytic cycle. A relatively good correlation between the onset potential for NER and the binding energy of adsorbed nitrogen on vacancy is obtained. RuN, CrN, and WN are predicted to be stable and active for NER with low onset potentials (from −0.23 to −0.55 V vs RHE) among all the nitrides studied here. NiN, RhN, PdN, IrN, and PtN were found unable to sustain the catalytic cycle of ammonia at ambient conditions. Instead, they might be interesting as potential reactants for the ammonia reaction.