A Roadmap of Sustainable Hydrogen Production and Storage: Innovations and Challenges

The present review offers a strategic roadmap for overcoming conventional photocatalyst limitations and emphasizes recent advancements in hybrid photocatalysts, thereby addressing electrode and topology-associated challenges for sustainable hydrogen (H₂) production and storage. Unlike traditional reviews, this paper explores the latest developments in hybrid photocatalysts and provides a thorough analysis of H₂ fuel technology, including water splitting, photocatalytic reactions, and storage issues. A detailed analysis of photoelectrochemical (PEC) water splitting, which mimics photosynthesis, to produce carbon-neutral H₂ and the importance of optimizing PEC devices with co-catalysts are highlighted. Advanced photocatalyst designs, including Z-scheme and S-scheme heterojunctions, doping, surface modifications, and copolymerization, are discussed and the impact of various materials, such as conjugated microporous polymers (CMPs), covalent organic frameworks (COFs), graphdiyne, MBene, TiO₂-based compounds, metal sulfides, and group III–V compounds, on PEC activity is examined. Furthermore, this review highlights strategies for improving photocatalyst performance, such as targeted doping, vacancy creation, and hybrid composite formation. Recommendations include designing cost-effective efficient hybrid photoelectrodes, maximizing light utilization, and simplifying PEC cell design. By addressing H₂ storage, transport, and conversion challenges, this review not only covers critical aspects of H₂ production but also provides a roadmap towards achieving a sustainable hydrogen future.