Boosting the interlayer-confined nitrate reduction reaction by in situ electrochemical potassium ion intercalation

Electrochemically converting nitrate ions back to valuable ammonia (NH 3 ) represents a sustainable alternative to the traditional Haber-Bosch process. However, NH 3 electrosynthesis is currently restricted by the low catalytic activities and Faradaic efficiency (FE) of NO 3 − -to-NH 3 . Here we report an interlayer-confined nitrate reduction reaction (NTRR) in a two-dimensional layered structure. The results indicate that in situ electrochemical K + intercalation expands the interlayer spacing, which triggers the NTRR between layers. The obtained α-Ni 0.902 Cu 0.098 (OH) 2 ultrathin nanosheets deliver high NTRR performance with an NH 3 yield rate of 13.4 mol g cat. −1 h −1 and O 3 − -to-NH 3 FE of 98.9% at −0.6 V, far exceeding those of Cu-based electrocatalysts. Moreover, the catalyst exhibits good cycling stability, which can sustain 20 successive cycles without obvious decay of activity and NH 3 FE. Meanwhile, in situ electrochemical Raman spectroscopy results unravel the NO 3 − -to-NH 3 pathway.