Direct electrodeposition of NiFe-based high-entropy compound on nickel foam for oxygen evolution reaction

Electrochemical water splitting represents a highly promising avenue for sustainable energy conversion and storage, paving the way for a future hydrogen-based society. This approach necessitates the development of durable and cost-effective electrocatalysts for the OER. In this study, we report the as-synthesized NiFe-based high-entropy compound grown on nickel foam via direct electrochemical deposition. Remarkably, electrodeposition onto 1×1 cm ² nickel foam was optimized by strategically varying critical parameters. Subsequently, the fabricated electrodes underwent evaluation for comprehensive water splitting within the identical flow cell under alkaline conditions. The best-performing sample, NiFe-2:1, required relatively low overpotentials of 232 mV to reach a current density of 10 mA cm ^-2 for the OER. The NiFe-2:1 hydroxides exhibit high entropy, which optimizes the flat-band potential (E _fb ) and carrier concentration (N _A ) in high-entropy NiFe-based electrocatalysts. This enhancement facilitates sensitive electron transfer, thereby reducing the kinetic barrier for the OER. Furthermore, this review thoroughly discusses potential degradation mechanisms of active sites and outlines corresponding mitigation strategies. It also offers insights into the discrepancies between research and the design of non-precious metal-based catalysts for the OER, as well as their implementation in practical devices.