Self‐Sacrificial Template‐Induced Fabrication of Sustainable Diode‐Type Micro‐Junction toward Supercapacitors and Green H₂ Evolution

Abstract Energy conversion and storage are the key challenges in green chemistry that have garnered significant attention in recent decades. Heterostructure materials, with their unique interfaces, robust architectures, and synergistic effects, show great promise in enhancing energy conversion and storage capabilities. However, the intricate relationship between their structural properties and performance requires further investigation. This study introduces a novel diode‐type interfacial micro‐junction fabricated from FeCo‐based layered double hydroxide (LDH) using a self‐sacrificial template‐induced method. The micro‐junction structure significantly enhances the material's electronic properties, enabling efficient charge separation and ion transport. As a result, the material demonstrates remarkable performance in both photocatalytic hydrogen evolution and supercapacitor applications. Specifically, the optimized material exhibits superior specific capacitance (1814.14 F g⁻¹ at 1 A g⁻¹), high energy density (61.6 Wh kg⁻¹), and excellent cycling stability (90.7% capacitance retention after 15 000 cycles) in coin cell supercapacitors. Additionally, the material's unique light‐harvesting capabilities and enhanced charge‐carrier dynamics make it a promising candidate for photocatalytic H₂ evolution at a rate of 577.8 µmol h⁻¹. This work not only advances the development of multifunctional materials for clean energy applications, but also opens new avenues for the design of high‐performance energy storage and conversion technologies.