Rational Designing of Nickel–Iron Containing Layered Double Hydroxide NiFe@LDH Electrocatalysts for Effective Water Splitting

The development and creation of cost-effective, chemically robust electrocatalysts to aid in the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) represent significant challenges within the realm of electrocatalytic water electrolysis. In this study, we synthesized a highly competent electroactive catalyst comprising nickel–iron-layered double hydroxide (LDH) using a simple hydrothermal approach. The resultant structure, characterized by well-interconnected metal ions arranged in nanospherical architectures, facilitated the formation of an enhanced electrochemical surface area rich in catalytically active sites, exhibiting harmonious effects. Maintaining the appropriate stoichiometric balance, exemplified by NiFe@LDH, proved essential in augmenting catalytic behavior for both OER and HER. The catalysts NiFe@LDH demonstrated overpotentials of 260 mV (76 mV dec–1) for OER and 138 mV (83 mV dec–1) for HER, achieving a current density of 10 mA cm–2 in 1 M KOH. Furthermore, NiFe@LDH showcased remarkable durability, enduring up to 100 h with a marginal reduction in current densities of 4.2 and 3.2% for OER and HER, correspondingly. Significantly, in the bifunctional two-electrode configuration featuring NiFe@LDH/NF//NiFe@LDH/NF, efficient electrolysis was achieved, maintaining a stable 10 mA cm–2 at a bias of 1.57 V for over 150 h, with a negligible of 4.6% current loss.