Self-Supported Porous Ni–Fe–W Hydroxide Nanosheets on Carbon Fiber: A Highly Efficient Electrode for Oxygen Evolution Reaction

Abstract

Structural and compositional modulation of low-cost hydroxide is important for making efficient electrocatalysts of the oxygen evolution reaction (OER), and it is an ongoing challenge. Here, Ni−Fe−W hydroxide complex by incorporation of tungsten into nickel−iron layered double hydroxide was proposed and investigated. As-formed Ni−Fe− W hydroxide nanosheets are highly porous and self-supported on the carbon fiber substrates, which promote the exposure of the active metal sites for significantly enhanced OER activity. Moreover, the as-introduced tungsten is evidenced to be in a W 6+ oxidation state which can facilitate charge transfer and electron capture and thereby decrease the critical conversion barrier of the absorbed OH − to O radical in OER. A series of Ni−Fe−W hydroxides were prepared, with the best molar ratio of Ni−Fe−W sources being 6:2:1. The optimal Ni 6 Fe 2 W-LDH@carbon fiber electrode delivers a low overpotential of 264 mV at 10 mA cm −2 and high stability (only 1.6% of the potential increase after 10 h) in alkaline electrolyte. Moreover, the structure of the constructed Ni−Fe−W hydroxide is evidenced to be stable and important for the electrocatalytically stable. The study is expected to open a new avenue in developing multiple hydroxides for low-cost and efficient electrocatalysts.

Zinc Ion Intercalation/Deintercalation of Metal Organic Framework-Derived Nanostructured NiO@C for Low-Transmittance and High-Performance Electrochromism

“…Figure d shows that a porous structure is uniformly generated on the sheet structure of the as-obtained NiO@C. It supports that the organic ligands in the MOF can effectively inhibit the aggregation of metal ions. The pores on the surface of the active materials will increase the contact areas between the electrolyte and the material and reduce the diffusion distance of ions within the material. , More importantly, the porous structure can reduce the electrostatic interaction between Zn 2+ and the embedded framework, which is conducive to the intercalation of Zn 2+ . The nanosheet structure increases the specific surface area of the composite and provides more reactive sites.…”

Electrodeposited Trimetallic NiFeW Hydroxide Electrocatalysts for Efficient Water Oxidation

“…The double‐layer capacitance ( C dl ) was calculated by plotting Δ J ( J a – J c ) at various scan rates using cyclic voltammetry (CV) in the potential window range of 0.2–0.3 V vs. Hg/HgO in 1 M KOH. The calculated slope value is twice of the C dl [74] . A rotating ring disk electrode (RRDE‐3 A) setup was used to study the faradaic efficiency of the catalyst.…”

“…The calculated slope value is twice of the C dl . [74] A rotating ring disk electrode (RRDE-3 A) setup was used to study the faradaic efficiency of the catalyst. The RRDE has a glassy carbon disk with an area of 0.126 cm 2 and a Pt ring with an area of 0.0314 cm 2 .…”

Advanced Layered Double Hydroxide-Based Electrocatalysts for Electrocatalytic Oxygen Evolution Reaction

“…Xu and co-workers reported 3D porous Ni6Fe2Wx-LDH electrocatalyst by a one-step synthesis for OER. [32] Ni6Fe2Wx-LDH has abundant defects edge active sites with porosity. The introduced tungsten is proved to be in W 6+ oxidation state, which can promote charge transfer and electron capture, thus reducing the critical transition barrier of OH to O radicals adsorbed in OER.…”