Unveiling the role of bismuth doping in NiFe layered double hydroxide catalysts: Synergistic electronic modulation for superior oxygen evolution activity

Abstract

The development of non-precious metal electrocatalysts with high catalytic activity and durability for oxygen evolution reactions (OER) is critical for electrochemical water splitting technologies. In this study, Bi-doped NiFe layered double hydroxide catalysts (NiFeBi LDH) were synthesized via a hydrothermal method, and their OER performance was systematically evaluated. The results demonstrated that NiFeBi LDH exhibited remarkable catalytic activity in 1.0 M KOH solution. Compared to NiFe LDH and some other similar catalysts reported in the literature, NiFeBi LDH demonstrates significant advantages with an overpotential of 85 mV, a Tafel slope of 48.01 mV·dec⁻¹, and a charge transfer resistance of 0.66466 Ω at a current density of 10 mA cm⁻². Meanwhile, NiFeBi LDH can trigger surface reconstruction and generate high-activity NiFeOOH species at a low overpotential. In situ Raman spectroscopy revealed the mechanism by which Bi doping enhances surface reconstruction during OER. Further density functional theory (DFT) calculations indicated that Bi doping significantly improved the OER activity of NiFeBi LDH. This study not only advances the understanding of the OER mechanism in NiFeBi LDH catalysts but also provides valuable insights for the design of efficient, low-cost non-precious metal electrocatalysts.