Highly enhanced electrocatalytic OER with facile electrodeposition of MIL–53(Fe)/NiAl–LDH/NF and NiAl–LDH/MIL–53(Fe)/NF

Abstract

This research investigates a new approach to improve the electrocatalytic rate of the Oxygen Evolution Reaction (OER), a key step in water electrolysis. The study focuses on two promising materials: MIL–53(Fe) and NiAl–LDH. MIL–53(Fe) offers several advantages: high catalytic activity, large surface area, and good chemical stability. NiAl–LDH is attractive due to its layered structure, tolerance to a wide range of pH levels, scalability, and cost-effectiveness. However, their limitations like low conductivity and restricted accessibility of active sites hinder their performance in water splitting applications. To address these limitations, novel composite thin films were created using a technique called layer–by–layer (LBL) electrophoretic deposition. These films, built on nickel foam (NF) substrates, included two configurations: MIL–53(Fe)/NiAl–LDH/NF and NiAl–LDH/MIL–53(Fe)/NF. The MIL-53(Fe)/NiAl-LDH/NF composite exhibited remarkable OER activity in alkaline electrolytes, requiring overpotentials of only 200, 270, and 370 mV to reach current densities of 20, 50, and 100 mA cm⁻², respectively. The Tafel slope of 54.86 mVdec⁻¹ suggests rapid reaction kinetics. Additionally, it demonstrated excellent long-term stability, lasting for at least 20 h. The success of the MIL–53(Fe)/NiAl–LDH/NF composite can be attributed to the LBL technique. This method creates a composite with a larger surface area, significantly improving OER efficiency. In contrast, the MIL–53(Fe)/NiAl–LDH/NF configuration had the opposite effect. The NF pores became blocked by the MIL–53(Fe) layer, reducing the overall surface area, hindering electron transfer, and thereby limiting oxygen production. The LBL deposition method used in this study proves its effectiveness in designing efficient electrocatalysts. This opens up possibilities for creating other multicomponent materials for energy applications. The findings provide valuable insights for future research on these promising composite materials, potentially leading to the development of cost-effective and high-performance catalysts for various electrochemical applications.