Hierarchical iron nickel oxide architectures derived from metal organic frameworks as efficient electrocatalysts for oxygen evolution reaction
Abstract In this study, a series of iron nickel oxide (Fe Ni O x architectures with different Fe/Ni ratios are synthesized by using corresponding Fe Ni based metal organic frameworks (MOFs) as self templates for the first time. The characterization on microstructures suggest that Fe/Ni ratio significantly affects the morphology and phase composition of Fe Ni O x architectures. The Fe rich samples exhibit spindle like structures while the Ni rich samples consist of irregular nanoparticle aggregates, and the higher Ni ratio is favorable for the formation of Fe Ni spinel strucutre in product. Serving as nonprecious electrocatalysts, the Fe Ni O x architectures exhibit the remarkable electrocatalytic activity toward oxygen evolution reaction (OER) in alkaline medium, which is found to be closely dependent on composition of Fe Ni O x catalysts. The active phase of spinel structured NiFe 2 O 4 plays a dominating role in enhancing the electrocatalytic OER activity of the Fe Ni O x architectures. Based on the X ray photoelectron spectroscopy (XPS) and Raman spectroscopy analysis, the possible OER mechanism of the Fe Ni O x architectures is unraveled as well.