Ruthenium modulated Ni-Co pyrophosphate architectures enabling accelerated oxygen evolution in anion exchange membrane electrolyzer

Abstract

The development of efficient and durable electrocatalysts remains crucial for sustainable production of hydrogen via water electrolysis. Herein, we report a ruthenium-modified nickel-cobalt pyrophosphate [(NiCo)(P2O7)] catalyst (Ru-NCP) as a class leading oxygen evolution electrode under alkaline conditions and its application in anion exchange membrane water electrolysis (AEMWE). The NiCo2O4 precursor was transformed into a pyrophosphate framework through phosphidation, followed by Ru deposition and thermal reduction under Ar/H2. Structural analyses (XRD, Raman, TEM, XPS) confirmed the formation of the (NiCo)(P2O7) lattice and Ruinduced modulation of metal oxidation states. Electrochemical studies revealed an overpotential of 1.567 V at 100 mA cm- 2 and stable operation at 400 mA cm- 2 for 24 h in 1.0 M KOH. Integrated into an AEMWE, Ru-NCP achieved 1.6 A cm-2 at 4.5 V with extended durability. The superior performance arises from Ru-mediated electronic reconfiguration and enhanced active site accessibility within the pyrophosphate matrix.