Pr-doped NiFe-layered double hydroxide on plasma-etched nickel foam as a high-efficiency electrocatalyst for oxygen evolution reaction

Abstract

Nickel-iron layered double hydroxide (NiFe-LDH), as a highly promising non-precious metal catalyst for the oxygen evolution reaction (OER), still suffers from several inherent drawbacks, including poor electrical conductivity, insufficient exposure of active sites, and a decline in performance under high current densities. These limitations severely restrict its practical application in the oxygen evolution reaction. Herein, a nanosheet morphology Pr-doped NiFe layered double hydroxide catalysts (Pr-NiFe-LDH) was synthesized in situ on the surface of Nickel foam modified by dielectric barrier discharge (DBD) plasma (PNF). The addition of Pr elements can effectively adjust the electronic structure of NiFe-LDH, change the position of the d-band center, and increase the number of active sites, thereby enhancing the catalytic activity. The overpotential of Pr-NiFe-LDH was reduced to 321 mV at 100 mA cm⁻², significantly lower than that of NiFe-LDH (342 mV) and even superior to that of commercial RuO₂ catalyst (441 mV). The density functional theory (DFT) study indicates that adding Pr to the surface of NiFe-LDH enhances its performance in the OER. This work not only deepened the understanding of the OER mechanism in the NiFe-LDH catalyst, but also provided valuable insights for the design of efficient, low-cost and noble-metal-free electrocatalysts.