Improving the hydrogen evolution performance of self-supported hierarchical NiFe layered double hydroxide via NH3-inducing at room temperature

Abstract

NiFe layered double hydroxide (NiFe-LDH) has been considered as a promising electrocatalyst for the oxygen evolution reaction (OER) in alkaline electrolytes. However, its electrocatalytic activity for the hydrogen evolution reaction (HER) is inferior. Here, we report a novel strategy for substantially improving the HER electrocatalytic activity of NiFe-LDH as well as retaining its OER performance through facile and low-consumption NH₃-inducing at room temperature. The representative sample (NiFe-LDH_2.18) shows a unique hierarchical architecture and a modulated electronic state, exhibiting more available active sites, more unobstructed channels for gas release, and faster electron/ion transfer rate. In an alkaline medium, NiFe-LDH_2.18 exhibits excellent HER catalytic activity with an overpotential of 95 mV at the current density of 10 mA cm⁻², being much superior to that of original NiFe-LDH. Moreover, its impressive OER performance is well retained, requiring an overpotential of 227 mV at the current density of 100 mA cm⁻². Thanks to the excellent HER/OER performance of NiFe-LDH_2.18, remarkable electrocatalytic activity toward full water splitting has been achieved.