Facile Synthesis of Sulfate-Intercalated CoFe LDH Nanosheets Derived from Two-Dimensional ZIF-9(III) for Promoted Oxygen Evolution Reaction

Abstract

Layered double hydroxide (LDH) has emerged as a promising electrocatalyst; however, the synthetic method usually requires high temperature and high pressure, and sulfate-intercalated LDH is rarely reported. Herein, the sulfate-intercalated CoFe LDH nanosheets were successfully fabricated at ambient temperature via a facile strategy, using two-dimensional ZIF-9(III) as a template and FeSO4 as both etchant and iron source. When the as-prepared sulfate-intercalated CoFe LDH acts as an electrocatalyst, it presents superior electrocatalytic performance for the oxygen evolution reaction (OER), requiring low overpotential (η@10 mA cm−2 = 218 mV) with a small Tafel slope of 59.9 mV dec−1 in 1.0 M KOH, which compares favorably with commercial RuO2 and most reported transition-metal electrocatalysts. The high catalytic activity of CoFe LDH might be ascribed to the large interlayer space distance originating from special SO42− ions and the strong synergistic effects between Fe and Co. This work provides a novel and feasible approach to designing highly efficient electrocatalysts based on advanced LDH materials for OER.

A green synthetic approach: crystalline–amorphous interface CoFe-LDH as a sustainable electrocatalyst for water oxidation with low cell voltage and evaluation of its sustainability standards

“…62 The increased activity could be due to the synergistic impact of Co and Fe, as well as the peculiar macropours architecture of the Co 4 Fe 6 -LDH catalysts. 63 Several investigations shown that Fe influences the regional electronic framework of Co–Fe materials, whereas CoOOH mostly served as a conductive and chemically stable host. According to Co 4 Fe 6 -LDH potential activity, 40 1.0 M KOH was in intimate contact with the dynamic region of the electrocatalyst surface.…”

Machine learning-assisted optimization of multi-metal hydroxide electrocatalysts for overall water splitting

“…64,65 A weaker peak observed at 523 cm −1 is attributed to metal–oxygen vibrations observed for FeOOH 34,66 or the Co–O ( A g ) symmetric stretching mode, 52 and is consistent with the previous spectra for CoFe LDHs. 17,67…”

“…64,65 A weaker peak observed at 523 cm À1 is attributed to metal-oxygen vibrations observed for FeOOH 34,66 or the Co-O (A g ) symmetric stretching mode, 52 and is consistent with the previous spectra for CoFe LDHs. 17,67 No differences were apparent between the X-ray diffraction (XRD) patterns of the samples from either synthesis method as well (Fig. S4.6, ESI †).…”

“…This includes the influence of intercalated electrolyte cations 15 as well as anions introduced into the interlayer spacing during the preparation of the LDH. [16][17][18] For example, molybdate, 19 and tungstate 20 intercalated nickel-iron (NiFe) LDHs have significantly enhanced oxygen evolution (OER) activities. Systematic compositional studies via high-throughput experimentations have been used to investigate the electrocatalytic activity of complex multi-metallic (oxy)hydroxides.…”

Construction of a ruthenium-doped CoFe-layered double hydroxide as a bifunctional electrocatalyst for overall water splitting

“…S4 (ESI†) owned two typical M-O peaks at 490.9 cm −1 and 574.8 cm −1 , which is consistent with the results of FTIR. 16,17 The Raman peaks of the samples after the HER and OER were located at a fairly similar wavenumber to the original one. For the blunter peaks of CoFe-ZLDH/Ru@NF after the HER, it can be attributed to the decrease of the grain size.…”