Construction of bimetallic phosphide Fe_xCo_1−xP nanostructured array as a bifunctional electrocatalyst for overall water splitting

The development of high-performance and low-cost bifunctional electrocatalysts is crucial for industrial-scale hydrogen production through water electrolysis. In this study, bimetallic Fe_xCo_1−xP nanosheet array electrocatalyst was prepared successfully by a hydrothermal method on the three-dimensional porous nickel foam substrate, which not only retains the excellent HER performance of CoP, but also effectively reduces the activation energy barrier during the OER process by incorporating Fe. This composite structure adjusts the local electronic structure, thereby enhancing the adsorption capacity of reaction intermediates at the active sites. Consequently, the nanosheet-like Fe_xCo_1−xP electrocatalyst without noble metal doping exhibits outstanding catalytic performance. Specifically, at the current density of 20 mA·cm^− 2 in 1.0 M KOH electrolyte, the overpotentials of Fe_0.2Co_0.8P nanosheet for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) are significantly lower than those of most electrocatalysts, measuring 162 mV and 234 mV, respectively. The results demonstrate the synergistic effect among the Fe, Co, and P elements, which facilitate the electrocatalytic process. Moreover, the synthesized Fe_0.2Co_0.8P nanosheet array electrocatalyst possesses a large active surface area and good conductivity, effectively promoting the kinetics of the electrocatalytic reactions. This work provides an effective approach for synthesizing efficient and inexpensive bifunctional electrocatalysts.