Oxygen anion engineering suppressed active sites segregation for long-lasting electrocatalytic water oxidation

Layered double hydroxides (LDHs) have emerged as a promising catalyst for oxygen evolution reactions (OER) due to their tunable intermediate layers structure and activity. However, long-lasting stability under large current still remains a great challenge due to undesirable active sites segregation. Herein, we develop a pre-electrocatalyst for alkaline OER, but it’s often limited by a sluggish reconstruction process required to form the active, high-value CoFe oxyhydroxide, a nitrite ion (NO 2 − ) doping strategy to synthesize cobalt-iron (CoFe) oxyhydroxide (CoFe-LDH-NO 2 − ) using in-situ growth and electrodeposition techniques, successfully inhibiting Fe segregation for improving the OER stability under a large current. At the atomic level, X-ray absorption spectroscopy indicates the introduction of NO 2 − enhances the M − O bonding, which helps to inhibit the segregation of iron during the evolution of the crystal lattice. In situ infrared and Raman spectroscopy further demonstrated that CoFe-LDH with NO 2 − engineering facilitates the rapid protonation of oxygen-containing intermediates, effectively converting them into the critical OOH* intermediates for kinetic-fast OER process, and then exhibiting a considerably enhanced long-term stability with a ten-fold improvement over CoFe-LDH without NO 2 − doping.