Atomically Dispersed Mn–Ir Sites on 2D Amorphous Carbon Materials Synergistically Boost Electrochemical Overall Water Splitting

Abstract Enhancing the activity and durability of noble‐metal‐based catalysts for overall water splitting is crucial for advancing sustainable energy conversion. In this study, a novel catalyst, PBN‐Ir/Mn, is reported, developed through a self‐healing process of the polyhexabenzocoronene network (PBN) that incorporates both Mn and Ir atoms. Aberration‐corrected high‐angle annular dark‐field scanning transmission electron microscopy (AC‐HAADF‐STEM) and X‐ray absorption spectroscopy (XAS) characterizations confirm a unique atomic‐scale Ir–Ir–Mn triangular structure on the porous PBN substrate. The synergy between Mn and Ir atoms leads to superior water electrolysis performance, with ultra‐low overpotentials of 11 mV for the hydrogen evolution reaction (HER) and 220 mV for the oxygen evolution reaction (OER) at 10 mA cm⁻². PBN‐Ir/Mn also achieves outstanding mass activities, reaching 425.92 A mg⁻¹ for HER and 152.28 A mg⁻¹ OER. Moreover, PBN‐Ir/Mn demonstrates exceptional durability in overall water splitting, maintaining stable performance over 100 h in a full‐cell setup, surpassing commercial benchmarks. Density functional theory (DFT) calculations reveal that Mn doping modifies the d‐band center of Ir, reducing the activation energy barriers and significantly enhancing both activity and stability. The high performance and stability of PBN‐Ir/Mn, combined with its scalability for gram‐scale synthesis, highlight its potential for industrial applications and multifunctional catalysis.