In Situ Vertical Growth of Fe–Ni Layered Double-Hydroxide Arrays on Fe–Ni Alloy Foil: Interfacial Layer Enhanced Electrocatalyst with Small Overpotential for Oxygen Evolution Reaction

Abstract

Layer double hydroxide (LDH) has been widely applied to electrocatalysis, especially toward the oxygen evolution reaction (OER), owing to its flexible layered structure and multifunctionality. Herein, FeNi LDH nanosheet arrays are directly synthesized on various metal foils by a facile hydrothermal method. Compared with single Fe or Ni substrates, the obtained FeNi LDH/ FeNi foil exhibited an ultrasmall onset overpotential of ∼90 mV, high catalytic activity (overpotential of 130 mV @ 10 mA/cm 2 ), and durable stability in 0.1 M KOH electrolyte. We also demonstrate, by utilizing density functional theory calculations, that the growth of the hydroxide interfacial layer between LDH and FeNi foil makes the LDH possess more favorable adsorption to the OH intermediate during OER than the pure LDH. This reveals that the vertical FeNi LDH arrays on the FeNi alloy substrate are prone to be an efficient catalyst toward OER.

Engineering Active Fe Sites on Nickel–Iron Layered Double Hydroxide through Component Segregation for Oxygen Evolution Reaction

“…The composition of the LDH catalysts was further verified by X‐ray photoelectron spectroscopy (XPS), as shown in Figure S5 in the Supporting Information. In the high‐resolution Ni 2p spectra (Figure S6 in the Supporting Information), Ni 2p 3/2 and 2p 1/2 peaks were centered at binding energies of 856.8 and 874.6 eV, respectively, indicating the existence of Ni 2+ . The binding energy peaks of Fe 2p 3/2 and 2p 1/2 were located at 709.8 and 712.2 eV, respectively (Figure S7 in the Supporting Information), demonstrating the presence of Fe 3+ .…”

“…In the high‐resolution Ni 2p spectra (Figure S6 in the Supporting Information), Ni 2p 3/2 and 2p 1/2 peaks were centered at binding energies of 856.8 and 874.6 eV, respectively, indicating the existence of Ni 2+ . The binding energy peaks of Fe 2p 3/2 and 2p 1/2 were located at 709.8 and 712.2 eV, respectively (Figure S7 in the Supporting Information), demonstrating the presence of Fe 3+ . The XPS results were in accordance with the XRD observations, further confirming the formation of NiFe LDH.…”

Ni−Fe (Oxy)hydroxide Modified Graphene Additive Manufactured (3D‐Printed) Electrochemical Platforms as an Efficient Electrocatalyst for the Oxygen Evolution Reaction

“…As can be seen in Table 1, several substrates, such as nickel foam, [9,15] gold, [14a] and glassy carbon, [16] electrodes, have been used for deposition of Ni 1-x Fe x OOH. Recently, Xiang et al [17] reported the use of FeÀ Ni alloy foil as a substrate to grow vertically aligned NiÀ Fe (oxy)hydroxide, which allows a facile access to the catalytic sites and a favourable adsorption of OH intermediate during OER. However, these electrodes lack transferability to "real world"/industrial applications.…”

Integrated Nanostructural Electrodes Based on Layered Double Hydroxides

“…Those iron‐substrate‐derived LDHs showed remarkable electrocatalytic stability for more than 6 000 hours (>8 months) at a large current density of 1 000 mA cm −2 owing to strongly coupled interface between LDH and substrate, and the ultrasmall crystalline domains within nanosheets. Up to now, a variety of LDHs have been successfully constructed on various substrates such as FeNi‐LDH/FeNi foil, NiFe‐LDH/graphene foil, NiAl‐LDH/carbon nanotube paper, CoAl‐LDH/reduced graphene oxide, ZnCr‐LDH/fluorine‐doped tin oxide (FTO), CoFe‐LDH/Cu mesh, and those synthesized pristine LDH‐INEs have brought about widespread attention in energy storage and conversion fields.…”