Advances and challenges in hydrogen generation using metal complex-semiconductor hybrid systems for sustainable energy applications

Sustainable energy sources have become a major research topic today, and research has intensified on efficient hydrogen production, which is a key component of the future hydrogen economy. Hybrid systems integrating semiconductors with complex transition metal compounds have made it possible to increase the efficiency of photocatalytic hydrogen production and minimize the consumption of precious metals. This review focuses on the state-of-the-art in photocatalytic hydrogen production, concentrating on modern catalytic hybrid systems that incorporate metal complexes of ruthenium, platinum, nickel, cobalt and iron. Particular emphasis is placed on the role of different ligand environments in tuning catalytic performance and hydrogen production yields. In addition, we critically evaluate the advantages and limitations of various hybrid materials, highlighting strategies for optimizing their photocatalytic activity. • The mechanisms for the H 2 photogeneration reactions in the presence of hybrid systems are presented. •Cobalt complexes on graphene oxide produce hydrogen efficiently and are simple to synthesis. •Nickel and iron compounds improve light use and rate up hydrogen formation. •Ruthenium on graphitic carbon nitride increases light absorption and reaction rate. •Hybrid systems of semiconductors and metal complexes boost photocatalytic hydrogen production.