Compositional Optimization of Alloy FexNiy(OH)2 Nanoparticles for Alkaline Electrochemical Oxygen Evolution

Alloy FeNi nanoparticles were synthesized and evaluated as electrocatalysts for the oxygen evolution reaction in alkaline electrolyte. Electron microscopy imaging indicates nanoparticles were formed with a spherical morphology, and initial elemental analysis suggests significant oxygen content in the bimetallic particles. A molar ratio range from 5:1 to 1:5 Fe:Ni in the assynthesized nanoparticles was tested. The effect of polyvinylpyrrolidone stabilizer on nanoparticle performance was also evaluated. Catalytic performance of the nanoparticles increased with decreasing Fe:Ni molar ratio and PVP:Ni molar ratio. Alloy nanoparticles synthesized with a Fe:Ni ratio of 1:5 and a PVP:Ni ratio of 0.001 resulted in an overpotential of 295 mV at 10 mA/cm2, a Tafel slope of 40 mV/dec, and a mass-based activity of 3343 mA/mg at 1.6 V vs. RHE