Role of Catalyst in Controlling N2 Reduction Selectivity: A Unified View of Nitrogenase and Solid Electrodes

The Haber–Bosch process conventionally reduces N 2 to ammonia at 200 bar and 500 °C. Under ambient conditions, i.e., room temperature and ambient pressure, N 2 can be converted into ammonia by the nitrogenase molecule and lithium-containing solid electrodes in nonaqueous media. In this work, we explore the catalyst space for the N 2 reduction reaction under ambient conditions. We describe N 2 reduction on the basis of the *N 2 binding energy versus the *H binding energy; we find that under standard conditions, no catalyst can bind and reduce *N 2 without producing H 2 . We show why a selective catalyst for N 2 reduction will also likely be selective for CO 2 reduction, but N 2 reduction is intrinsically more challenging than CO 2 reduction. Only by modulating the reaction pathway, like nitrogenase, or by tuning chemical potentials, like the Haber–Bosch and the Li-mediated process, N 2 can be reduced.