Interlayer expanded nickel-iron layered double hydroxide by intercalation with sodium dodecyl sulfate for enhanced oxygen evolution reaction

Abstract

Layered double hydroxides (LDH), a typical two-dimensional nanomaterial, has received vigorous attention in water splitting for its typically weak van der Waals interactions that can tunable for its interlayer spacing. Opening LDH with expanded interlayer is highly desirable to expose more active sites for electrocatalysis and more accessible surface for ion transfer in the interlayer, which can greatly boost the performance of LDH. Herein, interlayer expanded nickel-iron layered double hydroxide (NiFe-LDH) was fabricated by the intercalation with sodium dodecyl sulfate (SDS) using a one-pot hydrothermal route. For compassion, the NiFe-LDH without SDS were also prepared as hierarchical hollow spheres (NiFe-LDH HSs), while hollow spheres were transformed into hierarchical nanosheets (NiFe(SDS)-LDH NSs) with the addition of SDS. Moreover, the interlayer spacing of NiFe(SDS)-LDH NSs was effectively enlarged to 2.36 nm contrast to 0.77 nm of NiFe-LDH HSs. As expected, a highly enhanced oxygen evolution reaction (OER) performance was obtained on NiFe(SDS)-LDH NSs with a current density of 10 mA cm−2 at overpotential of 115 mV, while 225 mV for NiFe-LDH HSs. The intercalation of SDS in NiFe-LDH plays an indispensable role in boosting OER. It indicates the importance of enlarging the interlayer space of LDH for high-performance OER.