Influence on the Electrocatalytic Water Oxidation of M²⁺/M³⁺ Cation Arrangement in NiFe LDH: Experimental and Theoretical DFT Evidences

This contribution reports the effect of the iron content and M²⁺/M³⁺ ratio cation arrangement-distribution on the oxygen evolution reaction (OER) catalyzed by layered double hydroxides. The electrocatalysts, containing variable contents of Ni and Fe, were successfully prepared through a homogeneous precipitation method. The formation of LDH structure was verified by powder X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). Other properties were determined such as specific surface area, electrical conductivity, and surface basicity. First-principles DFT+U calculations complemented and supported the electrochemical results. According to both the electrochemical and simulation results, the increase of the catalytic activity for the OER on the presence of Fe³⁺ is closely related with the configuration and distribution of Fe and Ni cations in the brucite layer structure. The effect of iron is indirect, favoring the electron hopping on the Ni sites for certain local configuration.