Sulfur Engineering on NiFe Layered Double Hydroxide at Ambient Temperature for High Current Density Oxygen Evolution Reaction

The development of a cost-effective and easy-to-prepare oxygen evolution reaction (OER) catalyst for electrolyzers at large current density is highly desired. Herein, we designed a convenient strategy to fabricate a three-dimensional self-supported S2–-doped NiFe layered double hydroxide (NiFe-LDH)/Ni foam (NF) catalyst by a hydrothermal reaction and etching at ambient temperature. The as-obtained S2–-doped NiFe-LDH/NF (NiFe-LDH/NF-S-3h) with hierarchical porous nanosheets is beneficial for providing high density of active sites and accelerating the mass transport. Remarkably, NiFe-LDH/NF-S-3h exhibits a superior activity for the OER with a very low overpotential of 239 and 309 mV to deliver current densities of 100 and 500 mA cm–2 in alkaline medium. Additionally, NiFe-LDH/NF-S-3h also demonstrates excellent long-term stability at 500 mA cm–2 for 150 h, showing an excellent industrial application prospect. Moreover, density functional theory calculations and X-ray absorption spectroscopy reveal that the introduction of S2– can effectively optimize the electronic structure of the cationic active site and improve the adsorption and desorption capability of oxygenated intermediates. The present work may provide a relatively convenient method for designing highly active electrocatalysts for practical applications.