Ferric citrate corroding nickel foam to synthesize carbon quantum dots@nickel–iron layered double hydroxide microspheres for efficient water oxidation

Abstract

The design of oxygen evolution reaction (OER) catalysts with high catalytic efficiency and durability is of great significance for promoting hydrogen production via water electrolysis. Here, a one-step hydrothermal method was used to synthesize carbon quantum dots@nickel–iron layered double hydroxide (CQDs@NiFe-LDH) composites based on corrosion engineering. The introduction of carbon quantum dots (CQDs) effectively modulates the electronic structure and charge distribution of nickel–iron layered double hydroxide (NiFe-LDH), resulting in high oxygen evolution reaction with an overpotential of 257 mV at 100 mA cm⁻² and a small Tafel slope of 38.73 mV dec⁻¹. Furthermore, CQDs@NiFe-LDH can be operated continuously for 300 and 100 h without the significant performance degradation at a current density of 100 mA cm⁻² in 1 M KOH and seawater solutions, respectively, indicating high catalytic stability. The excellent OER capabilities of CQDs@NiFe-LDH is attributed to the fact that CQDs can not only modulate the electronic structure of NiFe-LDH but also facilitate the transfer of protons between intermediates during the oxygen evolution reaction (OER), thereby enhancing the material’s intrinsic catalytic activity.