Fig. 3: Characterizations of the effect of V modification on catalyst reconstruction.
From: Electrosynthesis of adipic acid with high faradaic efficiency within a wide potential window
a In situ Raman spectra of Ni(OH)2-NS (left) and NiV-LDH-NS (right) at OCP condition after pre-oxidized 60 seconds at 1.5 VRHE in 0.5 M KOH and 0.4 M cyclohexanone. In situ Raman spectra of b Ni(OH)2-NS and c NiV-LDH-NS in 0.5 M KOH + 0.4 M cyclohexanone under different potentials. In situ XANES spectra at Ni K-edge for Ni(OH)2-NS and NiV-LDH-NS in d 0.5 M KOH and e 0.5 M KOH with 0.4 M cyclohexanone. Insets are the magnified region of the spectra between 8342 and 8446 eV. f Valence states of Ni in Ni(OH)2-NS and NiV-LDH-NS at different potentials. g In situ Ni EXAFS spectra for NiV-LDH-NS before and after introducing cyclohexanone at different potentials. h Theoretical models of Ni(OH)2-NS and NiV-LDH-NS. Top: over Ni(OH)2-NS, slow reconstruction from Ni(OH)2-NS to NiOOH serves as RDS and the cyclohexanone reduces high-valence Ni species to maintain a low valence state of Ni via a chemical step to produce AA. Bottom: over NiV-LDH-NS, the reconstruction step is facilitated by V modification, leading to a shift of RDS from the reconstruction step to the chemical step. i Gibbs free energy changes for reconstruction processes of Ni(OH)2-NS and NiV-LDH-NS. Source data for a–j, and i are provided in Source Data file.
