2D CoFe-LDH Nanosheet-Incorporated 1D Microfibers as a High-Performance OER Electrocatalyst in Neutral and Alkaline Media

Abstract

Compositional-variation-induced CoFe-LDHs (with various Co:Fe ratio; LDH, layered double hydroxide) have been prepared via a simple wet-chemical method followed by the formation of 1D microfibers through electrospinning (ES) techniques. The as-synthesized 1D fiber with a Co/Fe ratio corresponding to a 0.5:1 microfiber (CoFe-LDH 0.5 fiber) showed the highest oxygen evolution reaction (OER) activity by demanding an overpotential value of 267 mV while the corresponding powder material demands an overpotential value of 312 mV at pH = 14. In addition, the neutral OER activity of the catalysts was also verified in 0.2 M phosphate buffer solution (PBS), and the same CoFe-LDH 0.5 fiber demands a lower overpotential value of 300 mV while the CoFe-LDH 1 fiber and CoFe-LDH 1.5 fiber demand 320 and 340 mV overpotential, respectively. Hence, we have obtained the interesting result that the incorporated 1D fibrous material with lower cobalt content showed a higher activity than the other fibrous materials. A magnetic study shows that the presence of cobalt ions with a lower concentration ensures the higher ferromagnetic (FM) interaction among the cobalt ions which in turn polarize the overall electronic spin of the hydroxide entity. The polarization of the electronic spin results in lowering the energy barrier by omitting the spin inversion barrier.

Self-Reconstruction of Fe-Doped Co-Metal–Organic Frameworks Boosted Electrocatalytic Performance for Oxygen Evolution Reaction

“…Based on ECSA-normalized LSV curves (Figure b,c), unsurprisingly, Co-MOF/Fe 10 shows the lowest overpotential at the given current density, suggesting its higher inherent OER activity than FeOOH and Co-MOF/Fe n ( n = 0, 5, 20, 30). Thus, the exceptional OER activity of Co-MOF/Fe 10 not only stems from its large ECSAs but is also closely related to its high inherent OER activity, which is thought to arise from the bimetallic synergistic effect between Co and Fe. ,, It can be demonstrated that the Fe doping strategy is able to improve the performance of the OER by all the above electrochemical data analysis.…”

“…Thus, the exceptional OER activity of Co-MOF/Fe 10 not only stems from its large ECSAs but is also closely related to its high inherent OER activity, which is thought to arise from the bimetallic synergistic effect between Co and Fe. 43,47,48 It can be demonstrated that the Fe doping strategy is able to improve the performance of the OER by all the above electrochemical data analysis.…”

Constructing an n–n junction between CoFe-LDH and NiCoP as bifunctional electrocatalysts for efficient overall water splitting

“…S7 †), are ascribed to O-H stretching vibration, H-O-H stretching vibration, adsorbed water molecules, the antisymmetric stretching vibration of carbonate species and the P-O-P stretching vibration, while the absorption band at a lower wavenumber below 800 cm −1 is mainly ascribed to metal-oxygen stretching and bending vibrations, which are related to a brucite-like structure. 25,[31][32][33][34] Moreover, the CoFe-LDH@NiCoP/NF has a surface area of 6.7 m 2 g −1 and a pore size of 15.34 nm. However, the surface area of CoFe-LDH/NF and NiCoP/NF is only 2.03 and 1.61 m 2 g −1 , respectively.…”

Application of a Nickel Complex for Water Oxidation under Neutral and Acidic Conditions

“…Water electrolysis toward oxygen and hydrogen production is being improved as a possible strategy to store renewable energy when the wind or sun is unavailable. − A limitation of water electrolysis is the oxygen evolution reaction (OER), which provides the electrons for a water reduction reaction. − However, OER is a sluggish and complicated reaction. Recently, Ni complexes have been extensively applied as OER (pre)­catalysts.…”