Reinforced Layered Double Hydroxide Oxygen‐Evolution Electrocatalysts: A Polyoxometallic Acid Wet‐Etching Approach and Synergistic Mechanism

Abstract

Nickel–iron‐based layered double hydroxides (NiFe LDHs) have attracted tremendous research and industrial interests for oxygen evolution reaction (OER) electrocatalysis. However, methodologies on simultaneous regulation of performance‐influencing factors remain scarce and their real synergistic effects are not clear enough. Herein, a versatile polyoxometallic acids (POMs) etching approach is reported to ingeniously reconstruct NiFe LDH, including 3D morphological nanotailoring, Fe3+ and α‐Ni(OH)2 active species reconfiguration, creation of multiple Ni, Fe, and O vacancies, and intercalation of POM polyanionic clusters. The experimental and theoretical data collaboratively unveil that control of the key performance‐influencing factors and their multiple synergistic mechanisms dominantly contribute to the step‐like OER performance enhancement. The reinforced electrocatalyst is further produced with low cost and high performance up to Ф180 mm in diameter, showing its feasibility and advancement of the promising configuration of NiFe LDH‐PMo12(+) II Ni@NiFe LDH(−) for alkaline anion‐exchange‐membrane electrode stack cells. Furthermore, to mathematically evaluate the evolution, a novel empirical formula is proposed for quantitative identification of structure–activity correlations, which offers an opportunity for first and fast reliability on materials screening.

Multiple regulation towards an all-in-one NiCuMo/MoOx heterostructure for improving alkaline hydrogen oxidation

“…Among these oxidized Mo, besides the Mo 6+ species arising from the surface oxide films formed upon exposure to air, Mo 5+ is the transition state in which Mo 4+ is oxidized in air, suggesting the existence of MoO x . 10 Correspondingly, the O 1s signal (Fig. 2d) can be deconvoluted into two peaks attributed to lattice and adsorbed O, confirming the formation of MoO x .…”

Engineering of PMo12@NiCo-LDH compositevia in situencapsulation-reassembly strategy for highly selective photocatalytic reduction of CO2to CH4

“…S4 †), which was caused by the inhibition of the ordered stacking of LDH layers along c-axis by PMo 12 during the reassembly step. 32,33 In the FT-IR spectra (Fig. 3b), the various vibration peaks observed at 0 min, 60 min, and 120 min clearly suggested the evolution during the in situ encapsulation-reassembly process.…”

Effect of Rare-Earth Element Doping on NiFe-Layered Double Hydroxides for Water Oxidation at Ultrahigh Current Densities

“…The symmetrical paramagnetic peak further confirmed the introduction of the oxygen vacancy at g = 2.004 in ESR spectra of NiFe LDH and NiFeLa LDH-2 (Figure S7). 53,54 The higher intensity of the ESR signal for NiFeLa LDH-2 strongly indicated the formation of more oxygen vacancies by La doping compared to the pristine NiFe LDH. This phenomenon, which is in accordance with previous reports, 33,55,56 can prompt a rapid OH − adsorption as mentioned above in the calculation of the OH − diffusion coefficient.…”