A review on oxygen evolution electrocatalysts based on the different Ni-Fe matrix composites

With the rapid development of the world economy, green energy, many methods of hydrogen and oxygen as the most popular green energy gases from water splitting are constantly emerging. Anodic oxygen evolution reaction (OER), as a half-reaction of water electrolysis involving the transfer of four electrons, is thermodynamically slow, leading to its poor performance. To solve this difficult problem, many oxygen evolutions of electrocatalytic materials have emerged, especially some three-dimensional materials, which can easily interact with nickel-iron, owing to advantages of controllable electronic channels and three-dimensional structures. But, the weak electrical conductivity and thermodynamic instability directly lead to weak oxygen evolution properties. Various modification methods have been invested, such as additions of transition metal cations or non-metal anions, the introduction of the conductive supports or agents, adjustment with the three-dimensional structures, formation of heterojunctions, etc, which can complement each other's superiorities, thus improving the oxygen evolution performances. The successful modification of these materials can illustrate the great opportunities for oxygen evolution functional materials, which also supplies a great possibility to replace the expensive electrocatalysts in the future. More importantly, catalytic composite materials have taken a firm step in the field of low-carbon environmental protection and green energy materials, meanwhile playing an important role in the field of artificial and sustainable energy development. [Display omitted] •Nickel-iron bimetallic materials accelerate four-electron motion through synergistic promotion and co-regulation.•The reaction efficiency is accelerated by dissociating and adjusting the bonding of anions and cations in NiFe layered hydroxides.•Through the design of metal center and surface defects, the mass activity of nickel-iron organic metal frame is improved.•The combination of spinel and NiFe-based materials regulated the mass transfer of electrons and ions in the interface layer.•This article can deepen the reader's understanding of the basic knowledge of oxygen evolution and different modification methods.