Related Experiment Video
Updated: Jun 29, 2025
09:02
Synthesis of Platinum-nickel Nanowires and Optimization for Oxygen Reduction Performance
Published on: April 27, 2018
7.8K
Iron Integration in Nickel Hydroxide Matrix vs Surface for Oxygen-Evolution Reaction: Where the Nernst Equation Does
Mohammad Saleh Ali Akbari1, Subhajit Nandy2, Keun Hwa Chae2
1Department of Chemistry, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan, 45137-66731, Iran.
The Journal of Physical Chemistry Letters
|March 25, 2024
Summary
This study compares two nickel-iron (NiFe) oxide forms for oxygen evolution. Results show a direct link between applied potential and oxidized nickel, differing from standard electrochemical models.
Area of Science:
- Electrochemistry
- Materials Science
- Catalysis
Background:
- The oxygen-evolution reaction (OER) is crucial for energy conversion technologies.
- Nickel-iron (hydr)oxides are promising OER electrocatalysts.
- Understanding structure-activity relationships is key to catalyst optimization.
Purpose of the Study:
- To compare the OER activity of two NiFe (hydr)oxide structures: surface Fe-doped (compound 1) and bulk Fe-incorporated (compound 2).
- To investigate the electrochemical behavior and oxidation mechanisms of these NiFe (hydr)oxides.
Main Methods:
- Electrochemical characterization of NiFe (hydr)oxide compounds.
- Visible spectroscopy for oxidation state analysis.
- Analysis of potential-charge relationships during OER.
Main Results:
- A direct proportionality was observed between applied potential and the concentration of oxidized nickel ions (V ∝ [oxidized Ni]).
- This relationship deviates from the logarithmic dependence predicted by the Nernst equation.
- Visible spectroscopy confirmed an increasing trend towards nickel oxidation.
Conclusions:
- The structural incorporation of Fe significantly influences the OER activity and electrochemical response of NiFe (hydr)oxides.
- The observed linear correlation between oxidized Ni(II) and applied potentials suggests unique oxidation mechanisms in these materials.
Related Concept Videos
02:59The Nernst Equation
40.8K
Nonstandard Reaction Conditions
The interconnection between standard cell potentials and various thermodynamic parameters such as the standard free energy change ΔG° and equilibrium constant K has been previously explored. For example, a redox reaction involving zinc(II) and tin(II) ions at 1 M concentration with Eºcell = +0.291 V and ΔG° = −56.2 kJ is spontaneous.
The interconnection between standard cell potentials and various thermodynamic parameters such as the standard free energy change ΔG° and equilibrium constant K has been previously explored. For example, a redox reaction involving zinc(II) and tin(II) ions at 1 M concentration with Eºcell = +0.291 V and ΔG° = −56.2 kJ is spontaneous.
40.8K
01:30Ladder Diagrams: Redox Equilibria
457
Ladder diagrams are useful tools for understanding redox equilibrium reactions, especially the effects of concentration changes on the electrochemical potential of the reaction. The vertical axis in the redox ladder diagrams represents the electrochemical potential, E. The area of predominance is demarcated using the Nernst equation.
Consider the Fe3+/Fe2+ half-reaction, which has a standard-state potential of +0.771 V. At potentials more positive than +0.771 V, Fe3+ predominates, whereas Fe2+...
Consider the Fe3+/Fe2+ half-reaction, which has a standard-state potential of +0.771 V. At potentials more positive than +0.771 V, Fe3+ predominates, whereas Fe2+...
457
01:23Redox Equilibria: Overview
564
A reduction-oxidation reaction is commonly called a redox reaction. In a redox reaction, electrons are transferred from one species to another rather than being shared between or among atoms. The reducing agent or reductant is the species that loses electrons and gets oxidized in the process. The species that gains electrons and gets reduced in the process is the oxidizing agent or oxidant. Redox reactions are represented as two separate equations called half-reactions, where one equation...
564
03:00Electrolysis
26.3K
In a galvanic cell, the electrical work is done by a redox system on its surroundings as electrons produced by the spontaneous redox reactions are transferred through an external circuit. Alternatively, an external circuit does work on a redox system by imposing a voltage sufficient to drive an otherwise nonspontaneous reaction in a process known as electrolysis. For instance, recharging a battery involves the use of an external power source to drive the spontaneous (discharge) cell reaction in...
26.3K
03:02Standard Electrode Potentials
43.8K
On comparing the reactivity of silver and lead, it is observed that the two ionic species, Ag+ (aq) and Pb2+ (aq), show a difference in their redox reactivity towards copper: the silver ion undergoes spontaneous reduction, while the lead ion does not. This relative redox activity can be easily quantified in electrochemical cells by a property called cell potential. This property is commonly known as cell voltage in electrochemistry, and it is a measure of the energy which accompanies the charge...
43.8K
02:58Balancing Redox Equations
52.1K
Electrochemistry is the science involved in the interconversion of electrical and chemical reactions. Such reactions are called reduction-oxidation, or redox reactions. These important reactions are defined by changes in oxidation states for one or more reactant elements and include a subset of reactions involving the transfer of electrons between reactant species. Electrochemistry as a field has evolved to yield sufficient insights on the fundamental principles of redox chemistry and multiple...
52.1K