Advancements in Graphdiyne‐Based Multiscale Catalysts for Green Hydrogen Energy Conversion

The urgent global demand for sustainable energy solutions has intensified research on efficient catalysts for green hydrogen production. As a uniquely structured 2D carbon allotrope with sp/sp 2 ‐cohybridized networks, graphdiyne (GDY) possesses exceptional chemical and electronic properties and structural tunability that address critical challenges in catalysis and energy conversion. This review systematically explores the cutting‐edge field of GDY‐based multiscale catalysts within sustainable energy conversion systems. The fundamental characteristics of GDY that enable precise atomic‐level engineering of active sites, including its intrinsic porosity, conjugated electronic system, and high intrinsic activity, were initially described, followed by discussions on hierarchical design strategies ranging from atomic‐scale coordination modulation to macroscale 3D architectures. Special emphasis is placed on the structure‒property relationships in hydrogen evolution, oxygen evolution, nitrogen reduction and nitrate reduction reactions. By critically discussing recent breakthroughs in GDY‐based multiscale catalytic systems, insights into the origin of the excellent catalytic activity, enhanced selectivity, and improved catalyst stability were obtained. The discussion extends to practical considerations for large‐scale synthesis and industrial implementation challenges. Finally, we propose a roadmap for advancing GDY catalysts through machine learning‐guided material discovery and operando characterization techniques, highlighting their transformative potential in achieving a carbon‐neutral hydrogen economy.