Tailored Entropy State of Atomic-Thick High-Entropy Analog Layer-Stacked Tetra-Metallic Hydroxide Surface Enables Efficient Durable Hydrogen Production.

The development of high-efficiency electrocatalysts for green hydrogen production via electrochemical water electrolysis is crucial for addressing the future energy crisis. Herein, a particular engineering approach is employed to tailor the entropy state by integrating the medium/high-entropy hybrid concept, utilizing an atomic-thick NiFeCoMnPt high-entropy analog layer-coated 2D tetra-metallic NiFeCoMn double-layered hydroxide nanosheet-like structure (NFCM-NFCMP LDH). The NFCM-NFCMP LDH material demonstrates outstanding hydrogen and oxygen evolution performances in 1.0 M KOH medium with a required overpotential of only 72 and 220 mV, respectively, to reach a current density of 10 mA·cm-2, thus resulting in a small cell voltage of 1.53 V for overall water splitting, and an advanced mass activity of 0.63 A · mg ( Pt + Ru O 2 ) - 1 at 1.75 V, approximately 5.7-fold higher than that of commercial Pt/C(-)//RuO2(+). The NFCM-NFCMP LDH(+,-) couple-derived anion exchange membrane electrolyzer requires a cell voltage of 1.75/2.12 V to operate at 0.5/1.0 A·cm-2 at 60°C and maintain stability for 1000 h. Theoretical studies reveal that unique interactions between atomic sites within the atomic high-entropy-like surface layer and between the NFCMP and NFCM LDH structures drive surface reconstruction, creating optimized electronic configurations that promote robust, high-performance catalysis.