High-entropy FeCoNiCrCe layered double hydroxides by facile pulse current electrodeposition as high performance electrocatalysts for the oxygen evolution reaction

Abstract

A high-entropy strategy can promote the electrocatalytic activity of catalysts through a synergistic electronic environment. In this work, a high-entropy FeCoNiCrCe LDH was in situ constructed on a nickel foam substrate via facile pulse current (PC) electrodeposition at room temperature in just 20 minutes. This electrode outperforms its counterpart prepared by direct current (DC) electrodeposition, with a low overpotential of 215 mV at 10 mA cm⁻² and a small Tafel slope of 45.15 mV dec⁻¹. Notably, it exhibited remarkable stability during a 7-day chronopotentiometric test at 50 mA cm⁻². The enhancements arise not only from the synergistic effect of five-metal composition, but more importantly, from the microstructural advantages of the PC-prepared electrode, which are revealed from a novel perspective by comparison with its DC-prepared counterpart electrode. which are revealed from a novel perspective by comparison with its DC-prepared electrode, which served as the counterpart. The optimized surface morphology with uniform element distribution and similar content by PC electrodeposition enables more effective electronic structure modulation of the active sites by Cr and Ce in the local micro-region. Moreover, the near-equal element composition in FeCoNiCrCe is conducive to increasing the configuration entropy, making the high-entropy stabilization effect more pronounced, thereby leading to enhanced structural stability and OER durability compared to the DC counterpart.