Exploring Ir-doped NiFe-LDH nanosheets <i>via</i> a pulsed laser for oxygen evolution kinetics: <i>in situ</i> Raman and DFT insights

Abstract

Water electrolysis is one of the most satisfactory technologies for the generation of clean hydrogen energy by splitting water molecules without any harmful byproducts. However, its widespread application is severely restricted due to the paucity of suitable electrocatalysts for the oxygen evolution reaction (OER). Herein, we rationally designed iridium-doped NiFe-layered double hydroxide (NiFeIr-LDH) nanosheets via a novel and facile pulsed laser irradiation strategy. Remarkably, the NiFeIr-LDH nanosheets exhibited superior oxygen evolution reaction (OER) performance, exhibiting a lower overpotential (246 mV at 10 mA cm(-2)) compared to both NiFe-LDH (345 mV) and benchmark IrO2 (327 mV) in a 1 M KOH electrolyte. Furthermore, NiFeIr-LDH nanosheets showed outstanding catalytic stability for 12 h. Besides, in situ/operando Raman spectroscopy and theoretical studies revealed the effective modulation of the electronic structure of NiFe-LDH after Ir doping, leading to an improved performance in the OER. Most impressively, an alkaline water electrolyzer with NiFeIr-LDH(+)parallel to Pt/C(-) needed only a minimum cell voltage of 1.53 V to supply 10 mA cm(-2) compared to that of an IrO2(+)parallel to Pt/C(-) electrolyzer (1.62 V at 10 mA cm(-2)). This work provides new insights into the development of greatly efficient and durable OER electrocatalysts for industrial applications in alkaline water electrolyzers.