Morphology Engineering of Hollow g‐C ₃ N ₄ Nanotubes via Hydrogen Bond‐Mediated Self‐Assembly for Exceptional Photocatalytic Hydrogen Evolution

Abstract Amidst growing energy demands and environmental concerns, photocatalytic water splitting for hydrogen production offers a sustainable solution, yet efficient photocatalyst design remains challenging. This work addresses the limitations of graphitic carbon nitride (g‐C 3 N 4 ), such as restricted light absorption, low surface area, and poor charge separation, by innovatively engineering its nanostructure. In this study, we report a hydrogen bond‐mediated strategy to construct hollow g‐C 3 N 4 nanotubes (HCNT) via supramolecular pre‐organization of melamine and cyanuric acid (CA) within ethylene glycol (EG), followed by calcination. Synergistic hydrogen bonding between EG and CA directs precursor curvature, enabling the formation of well‐defined nanotubes with a significantly enlarged specific surface area (102.24 m 2 g −1 ), enhanced hydrophilicity, optimized band structure, and superior charge separation efficiency. Consequently, the developed HCNT catalyst achieves an exceptional visible‐light photocatalytic H 2 evolution rate of 14,409 µmol g −1 h −1 , representing an 11‐fold enhancement over bulk g‐C 3 N 4 and surpassing most reported g‐C 3 N 4 ‐based catalysts. Our work establishes a green, template‐free morphology‐engineering paradigm through rational hydrogen bond manipulation, advancing the design of efficient photocatalysts for solar fuel generation.