A facile co-precipitation synthesis of robust NiFe phosphate electrocatalysts for efficient oxygen evolution in AEMWE

In this study, a straightforward and cost-effective co-precipitation method is employed to synthesize nickel iron phosphate(NiFe Pi) nanomaterials for oxygen evolution reaction (OER) electrocatalysis. The results demonstrate that the OER electrocatalytic activity of these materials are highly sensitive to the ratio of Ni and Fe precursors. When the nickel‑iron ratio is 4.5:1, the amorphous catalyst exhibits an impressively low overpotential of only 178 mV at a current density of 10 mA/cm 2 in 1 M KOH solution, with a Tafel slope as low as 47.05 mV/dec, indicating superior recation kinetics. The influence of different Ni/Fe ratios on the performance of NiFe Pi catalysts is also thoroughly discussed. The synthesized NiFe Pi catalysts were further utilized to fabricate membrane electrode assemblies (MEAs) for applications. Single cell testing revealed that the Ni 4.5 Fe Pi catalyst, with a mass loading of 1.5 mg/cm 2 in the MEA, achieved the lowest working potential of 1.81 V at a current density of 1 A/cm 2 . This outstanding performance highlights its significant potential for commercial applications in the field of electrolysis. • Ni and Fe elements work synergistically to enhance the electrocatalytic activity. • The effect of iron content in structure and electrochemical properties was investigated. • NiFe Pi-15:1 delivers a low OER overpotential of 178 mV at 10 mA/cm 2 and a potential of 1.81 V at 1 A/cm 2 in an AEMWE setup.