Highly active FeNiOOH nanoflower structured catalyst achieving efficient oxygen evolution reaction under industrial strong alkaline conditions

The generation of green hydrogen is considered one of the most promising methods to address energy issues. This study synthesized a FeNiOOH catalyst with a two-dimensional nanoflower structure on a nickel foam substrate via a hydrothermal method, demonstrating excellent oxygen evolution reaction (OER) activity. At a current density of 10 mA cm^-², the OER overpotential of FeNiOOH is 265 mV. The specific surface area of FeNiOOH can reach 65 m² g^-¹ , with a pore size distribution of 6.5 nm, allowing for more significant adsorption of hydroxide ions (OH^-) on the surface. Concentration activity coefficients indicate that the activity of FeNiOOH catalysts is more sensitive to changes in KOH concentration. As the concentration of KOH solution increases, the high-valent NiOOH/FeOOH in the FeNiOOH catalyst exhibits good adaptability to alkaline solutions, achieving a mass activity of 263 A g^-¹ in 6 M KOH solution, which is a 5.9-fold increase compared to the 1 M testing condition (44.3 A g^-¹). Furthermore, after 5000 CV cycles, there was no performance degradation, and after a 30-hour chronopotentiometry evaluation, the potential degradation of the catalyst was negligible, demonstrating excellent stability. This study provides insights into the rational design of high-activity and high-stability OER catalysts and lays a foundation for developing efficient catalysts under industrial-scale conditions.