Unraveling the Fe-Dependent Phase Evolution and Structure of Ni-Fe/γ-Al2O3 Catalysts: A Combined Experimental and Computational Study

Nickel–iron (Ni-Fe) catalysts are widely used in industry due to their cost-effectiveness and versatile catalytic properties. This work investigates the structural and morphological characteristics of Ni-Fe catalysts supported on γ-Al2O3, synthesized with varying Ni/Fe atomic ratios (from 1:1 to 20:1). The catalysts were characterized using a combination of experimental techniques including X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning and transmission electron microscopy (SEM/TEM), and selected-area electron diffraction (SAED). Theoretical modeling using the USPEX evolutionary algorithm complemented the experimental data by predicting stable Ni-Fe crystal structures. The results revealed uniform metal distribution on the support with particle sizes ranging from 4.1 to 4.5 nm. SAED analysis confirmed the formation of an intermetallic FeNi phase, particularly in samples with higher iron content. This study demonstrates Ni-Fe interaction effects and will be of interest to researchers in catalysis and materials science working on the development of bimetallic systems.