Ar Plasma-Assisted SO32– Intercalation into NiFe Layered Double Hydroxides for Improved Performance in the Oxygen Evolution Reaction

Chemical intercalation plays a crucial role in enhancing the performance of nickel–iron layered double hydroxide (NiFe LDH) catalysts for the oxygen evolution reaction (OER). By introducing specific ions, the catalytic sites within NiFe LDH are optimized, thereby facilitating efficient water oxidation. In this study, we inserted SO₃^2– into NiFe LDH using Ar plasma. This process created a two-dimensional (2D)–three-dimensional (3D) petal-shaped p-NiFe LDH–SO₃^2– electrode. The p-NiFe LDH–SO₃^2– composite shows an excellent electrocatalytic performance. At a current density of 10 mA cm^–2, the overpotential is just 194 mV. During a long-term OER test at the same current density, the overpotential changes by only 1.57%. SO₃^2– has a strong electrodissociation effect, keeping metal ions in a high valence state and producing NiOOH/FeOOH. It also increases interlayer spacing, leading to more active sites and better OER performance. The results indicate that using Ar plasma technology to prepare the SO₃^2– intercalated NiFe LDH is advantageous. This method offers low energy consumption, precise control, and simple processes. Compared with previous studies, this technology enhances the intercalation efficiency of SO₃^2–. It also allows changes in the interlaminar spacing of LDH, which helps create more active sites.