Efficient O–O Coupling at Catalytic Interface to Assist Kinetics Optimization on Concerted and Sequential Proton–Electron Transfer for Water Oxidation

Abstract

A catalyst kinetics optimization strategy based on tuning active site intermediates adsorption is proposed. Construction of the M-OOH on the catalytic site before the rate-determining step (RDS) is considered a central issue in the strategy, which can optimize the overall catalytic kinetics by avoiding competition from other reaction intermediates on the active site. Herein, the kinetic energy barrier of the O−O coupling for as-prepared sulfated Co-NiFe-LDH nanosheets is significantly reduced, resulting in the formation of M-OOH on the active site at low overpotential, which is directly confirmed by in situ Raman and charge transfer fitting results. Moreover, catalysts constructed from active sites of highly efficient intermediates make a reliable model for studying the mechanism of the OER in proton transfer restriction. In weakly alkaline environments, a sequential proton−electron transfer (SPET) mechanism replaces the concerted proton−electron transfer (CPET) mechanism, and the proton transfer step becomes the RDS; high-speed consumption of reaction intermediates (M-OOH) induces sulfated Co-NiFe-LDH to exhibit excellent kinetics.

Recent progress in hierarchical nanostructures for Ni-based industrial-level OER catalysts

“…For Ni-containing materials with hierarchical structures, the surface reconstruction to NiOOH, the OER active species, is widely confirmed by in situ spectra, such as Raman and X-ray absorption fine structure (XAFS). 49,64,65 Along with the formation of NiOOH on the reconstructed surface, Co or Mn species, if available, are also involved in MOOH. In situ X-ray absorption near edge structure (XANES) spectroscopy reveals that the surface of Mn-CuCo 2 Se 4 /NF evolves into an oxyhydroxide-like (MOOH) active phase after the OER process, in which CoOOH forms at 1.10–1.40 V vs. RHE (Fig.…”

Molecular Mechanisms of Oxygen Evolution Reactions for Artificial Photosynthesis

“…The formation of M-OOH on the active site at low overpotential was directly confirmed in 1 M KOH solution by in situ Raman and charge transfer fitting results. In a weakly alkaline environment of 0.1 M KOH, a sequential proton-electron transfer mechanism replaces the concerted proton-electron transfer mechanism, and the proton transfer step becomes the rate-determining step (RDS) as illustrated in Figure 16 [233].…”

“…Oxygen 2023, 3, FOR PEER REVIEW 29 weakly alkaline environment of 0.1 M KOH, a sequential proton-electron transfer mechanism replaces the concerted proton-electron transfer mechanism, and the proton transfer step becomes the rate-determining step (RDS) as illustrated in Figure 16 [233]. A Pt-induced NiFe-LDH (Pt-NiFe LDH) nanosheet was synthesized and large current density electrodes could be achieved in OER as well as HER [234].…”

“…The active sites changed from Fe cations to Ni cations during OER and the OER dynamics were significantly improved [236]. The hierarchical bimetal nitride/hydroxide (NiMoN/NiFe LDH) array exhibits the industrially re- [233] with permission from the American Chemical Society.…”

“…For Co-NiFe-LDH nanosheet, weakening alkaline concentration changes rate-determining step (RDS) from the release of O 2 to the oxo radical formation. Reproduced from ACS Nano 2023[233] with permission from the American Chemical Society.…”