Atomically Dispersed W1–O3 Bonded on Pd Metallene for Cascade NO Electroreduction to NH3

Electrocatalytic NO reduction to NH3 (NORR) offers a prospective method for removing hazardous NO and producing valuable NH3 simultaneously. Herein, we demonstrate that atomically dispersed W on Pd metallene (W1Pd) can be an efficient and robust NORR catalyst. Atomic coordination characterizations unravel that W single atoms exist as W1–O3 moieties bonded on Pd metallene. In situ spectroscopic measurements and theoretical calculations reveal the synergistic cascade effect of W1–O3 and Pd metallene to promote the NORR energetics of W1Pd, in which the activation and hydrogenation of NO occur on W1–O3, while Pd metallene dissociates H2O and donates protons required for hydrogenation of NO to NH3. Consequently, W1Pd exhibits an NH3 yield rate of 758.5 μmol h–1 cm–2 with an NH3-Faradaic efficiency of 91.3% in a flow cell (272.1 μmol h–1 cm–2 and 93.7% in H-type cells), ranking almost the highest performance among all reported NORR catalysts.