NiFeCr Hydroxide Holey Nanosheet as Advanced Electrocatalyst for Water Oxidation

Abstract

By introducing chromium into a nickel-iron layered double hydroxide (LDH), a nickel iron chromium hydroxide nanomesh catalyst has been achieved on nickel foam substrate via electrodeposition followed by partial etching of chromium. The electrodeposited chromium acts as a sacrificial template to introduce holes in the LDH to increase the electrochemically active surface area, and the remaining chromium synergistically modulates the electronic structure of the composite. The obtained electrode shows extraordinary performance for oxygen evolution reaction and excellent electrochemical stability. The onset potential of the as-prepared electrode in 1 M KOH is only 1.43 V vs RHE, and the overpotential to achieve a high current density of 100 mA·cm is only 255 mV, outperforming benchmark nonprecious NiFe hydroxide composite electrode in alkaline media.

NiFeCo oxide as an efficient and sustainable catalyst for the oxygen evolution reaction

“…Binary oxides and there complex systems have been developed with metals that are abundant in the earth's crust for effective water catalytic activity. The incorporation of Fe into nickel oxide enhances catalytic activity by modifying the local electronic structure, conductivity, and electrochemically active catalytic sites . Modification of the electronic band structure of the host oxide or hydroxide lattice by doping it with a metal can thus promote intermediate reactions that enhance catalytic kinetics .…”

“…The incorporation of Fe into nickel oxide enhances catalytic activity by modifying the local electronic structure, conductivity, and electrochemically active catalytic sites. 19,20,[26][27][28][29] Modification of the electronic band structure of the host oxide or hydroxide lattice by doping it with a metal can thus promote intermediate reactions that enhance catalytic kinetics. 30,31 Although a vast number of binary and ternary multielement catalysts have been reported, the catalysts still suffer from poor electrochemical stability, which limits their large-scale applicability.…”

Design of Multi‐Metallic‐Based Electrocatalysts for Enhanced Water Oxidation

“…The OER performance mechanism of NiFeCr LDH was discussed systematically: (1) the incorporation of Cr improves the conductivity; (2) Cr is partially dissolved in alkaline media generating a porous nanomesh structure with enlarged ECSA; (3) the synergistic effect emanated from Cr invasion generates more active β‐NiOOH intermediate; (4) under OER potential, Cr oxidizes into 6+ state and Ni oxidizes to a relatively lower oxidation state (≤3+). In other words, Ni is “cathodically protected” and more active β‐NiOOH in ternary NiFeCr composite is produced during OER . Other ternary systems such as NiCoFe and NiFeV LDHs were also developed as highly active OER catalysts .…”

“…[83,114] Our group also developed Cr-doped NiFe and CoFe hydroxide composites ( Figure. 8d-e) as advanced OER catalyst that outperformed the benchmark NiFe and CoFe LDH catalysts. [89,90,115] The OER performance mechanism of NiFeCr LDH was discussed systematically: (1) the incorporation of Cr improves the conductivity; (2) Cr is partially dissolved in alkaline media generating a porous nanomesh structure with enlarged ECSA; (3) the synergistic effect emanated from Cr invasion generates more active β-NiOOH intermediate; (4) under OER potential, Cr oxidizes into 6 + state and Ni oxidizes to a relatively lower oxidation state (� 3 +). In other words, Ni is "cathodically protected" and more active β-NiOOH in ternary NiFeCr composite is produced during OER.…”

Hydrotalcite-Type Materials Electrodeposited on Open-Cell Metallic Foams as Structured Catalysts

“…The electrodeposition of hydroxides was originally developed for the modification of small and simple-shaped electrodes with Ni(OH) 2 [33,34] and it was later extended to the deposition of more complex hydrotalcite-type (HT) compounds, also called layered double hydroxides, with general formulaand Co/Al or Co/Cr HTs [36] were initially synthesized onto a Pt-foil cathode then Ni/Co, Ni/Fe, and Co/Fe formulations were applied as sensors [37], redox supercapacitors [38,39] and, more recently, as electrocatalysts, mainly for oxygen evolution reaction [40][41][42]. In these two latter fields, there is a growing interest in replacing conventional 2D by 3D supports such as fibers [43,44] and open-cell foams [45][46][47].In this context, we reported for the first time in 2008 the electro-base generation method to coat FeCrAlloy foams with HT compounds for the preparation of H 2 production structured catalysts [48]. Later, electrodeposition has been used to coat FeCrAlloy foams by Rh [49], Pt [50] and Pt-CeO 2 [51], as gas-phase structured catalysts.…”