Heterostructure and atomic doping engineering in 3D Co₂CrO₄@Cr-NiFe LDH/CF nanosheet arrays for efficient electrocatalytic oxygen evolution

The oxygen evolution reaction (OER) is usually considered a major obstacle to electrochemical water splitting, primarily because of its sluggish kinetics. Developing an effective and durable catalyst for the OER is indispensable for overcoming this challenge. In this study, a three-dimensional nanomaterial with a unique heterostructure (Co₂CrO₄@Cr-NiFe LDH/CF) was obtained by the deposition of Cr-doped double hydroxide (Cr-NiFe LDH) on Co₂CrO₄ nanosheet arrays grown on copper foam (Co₂CrO₄/CF). In particular, the catalyst had a current density of 100 mA cm^-2 at a low overpotential of just 257 mV, a high turnover frequency (TOF) of 10.21 s^-1 at an overpotential of 300 mV and a Tafel slope of merely 72 mV dec^-1. This indicated that Co₂CrO₄@Cr-NiFe LDH/CF exhibited outstanding catalytic efficiency. Moreover, the catalyst exhibited stability for a duration of 40 h at a current density of 100 mA cm^-2. The study introduces an innovative approach for the superior design of an OER catalyst and offers a significant reference for investigation within the realm of renewable energy.