Advancing electrocatalytic nitrogen fixation: insights from molecular systems

Nitrogen fixation has a rich history within the inorganic chemistry community. In recent years attention has (re)focused on developing electrocatalytic systems capable of mediating the nitrogen reduction reaction (N₂RR). Well-defined molecular catalyst systems have much to offer in this context. This personal perspective summarizes recent progress from our laboratory at Caltech, pulling together lessons learned from a number of studies we have conducted, placing them within the broader context of thermodynamic efficiency and selectivity for the N₂RR. In particular, proton-coupled electron transfer (PCET) provides an attractive strategy to achieve enhanced efficiency for the multi-electron/proton reduction of N₂ to produce NH₃ (or NH₄⁺), and electrocatalytic PCET (ePCET) via an ePCET mediator affords a promising means of mitigating HER such that the N₂RR can be achieved in a catalytic fashion.