Ir single atoms on NiFeZn-LDH matrix for exceptional oxygen evolution reaction

To address the sluggish kinetics of the oxygen evolution reaction (OER), a potential approach is to rationally design and fabricate extremely effective single atom catalysts (SACs). Using an appropriate matrix to stabilize single-atom active centers with optimal geometric and electronic structures is crucial for enhancing catalytic activity. Herein, we report the design and fabrication of Ir single atoms on NiFeZn layered double hydroxide (Ir-SAC/NiFeZn-LDH) electrocatalyst for highly efficient and stable OER. It is investigated that the NiFeZn support exhibits abundant defect sites and unsaturated coordination sites. These sites function to anchor and stabilize single Ir single atoms on the support. The strong synergetic electronic interaction between the Ir single atoms and the NiFeZn matrix resulted in remarkable OER performance of the as-fabricated Ir-SAC/NiFeZn catalyst. With a loading Ir content of 1.09 wt.%, this catalyst demonstrates a highly stable OER activity, with an overpotential of 196 mV at 10 mA·cm⁻² and a small Tafel slope of 35 mV·dec⁻¹ for the OER in a 1 M KOH solution. These results significantly surpass the performance of the commercially available IrO₂ catalyst.