High‐Entropy Alloy Nanoflower Array Electrodes with Optimizable Reaction Pathways for Low‐Voltage Hydrogen Production at Industrial‐Grade Current Density

Abstract Developing sufficiently effective non‐precious metal catalysts for large‐current‐density hydrogen production is highly significant but challenging, especially in low‐voltage hydrogen production systems. Here, we innovatively report high‐entropy alloy nanoflower array (HEANFA) electrodes with optimizable reaction pathways for hydrazine oxidation‐assisted hydrogen production at industrial‐grade current densities. Atomic‐resolution structural analyses confirm the single‐phase solid‐solution structure of HEANFA. The HEANFA electrodes exhibit the top‐level electrocatalytic performance for both the alkaline hydrogen evolution reaction (HER) and hydrazine oxidation reaction (HzOR). Furthermore, the hydrazine oxidation‐assisted splitting (OHzS) system assembled with HEANFA as both anode and cathode exhibits a record‐breaking performance for hydrogen production. It achieves ultralow working voltages of 0.003, 0.081, 0.260, 0.376, and 0.646 V for current densities of 10, 100, 500, 1 000, and 2 000 mA cm−2, respectively, and remarkable stability for 300 h, significantly outperforming those of previously reported OHzS systems and other chemicals‐assisted hydrogen production systems. Theoretical calculations reveal that extraordinary performance of HEANFA for OHzS is attributed to its abundant high‐activity sites and optimizable reaction pathways in HER and HzOR. In particular, HEANFA enables intelligent migration of key intermediates during HzOR, thereby optimizing the reaction pathways and creating high‐activity sites, ultimately endowing the extraordinary performance for OHzS.