FeOOH@CoP/NF heterointerface catalyst for electrocatalytic water dissociation in alkaline medium

Abstract

The synthesis of a stable and extremely active catalyst for hydrogen (HER) and oxygen evolution reactions (OER) is still a significant obstacle to the industrialization of hydrogen energy. This work demonstrates a stable and highly catalytic active FeOOH@CoP/NF nanostructured heterointerface for overall water splitting applications. The CoP/NF shows the lowest overpotential of 153 mV for HER, and FeOOH@CoP/NF shows the overpotential of 144 mV for OER at a current density of 10 mA/cm² under an alkaline medium. A full cell constructed with CoP/NF|| FeOOH@CoP/NF exhibits a cell voltage of 1.51 V and 1.75 V, respectively, to achieve a current density of 10 mA/cm² and 100 mA/cm² for total water splitting applications. Furthermore, the catalyst robustness tested for 30 h at 100 mA/cm² current density reveals surface reconstruction, which still enhances the activity of the electrocatalyst. The Co²⁺ rich CoP metal complex creates an ensemble effect during the HER process whereas, Co³⁺ and Fe²⁺ organize a barter system leading to a better OER process in FeOOH–CoP interface. These findings demonstrate the potential use of CoP/NF || FeOOH@CoP/NF in water electrolysis and may offer a non-precious metal phosphate hydroxide electrocatalysts in real-world industrial applications.