Emerging inorganic-organic hybrid photocatalysts for solar-driven overall water splitting: progress and perspectives

The pursuit of sustainable energy technologies has long inspired the development of efficient photocatalysts capable of converting solar energy into hydrogen (H₂) via overall water (H₂O) splitting. While inorganic semiconductors, such as metal oxides, oxynitrides, and oxysulfides, have demonstrated reasonable activity and robustness, their intrinsic limitations in light harvesting and charge separation continue to hinder their photocatalytic performance. Conversely, organic semiconductors offer compelling advantages, including tunable electronic structures, visible-light absorption, and synthetic versatility. However, their application in overall H₂O splitting remains constrained by short exciton diffusion lengths, low carrier mobility, and poor activity in multi-electron processes. Recently, integrating organic and inorganic materials into hybrid photocatalysts has emerged as a powerful strategy to overcome these bottlenecks. By synergistically combining the efficient charge transport of inorganic frameworks with the structural adaptability and optoelectronic tunability of organic materials, rationally designed hybrid systems have shown remarkable potential in enhancing light utilization, facilitating exciton dissociation, and suppressing recombination. These advances not only improve overall H₂O splitting efficiency but also open new avenues for photocatalyst design. This review critically examines the fundamental principles, interfacial interactions, and photophysical mechanisms underpinning inorganic-organic hybrid photocatalysts for solar-driven overall H₂O splitting. We highlight recent breakthroughs, analyse the remaining scientific and engineering challenges, and propose strategic directions for next-generation hybrid systems with improved scalability, efficiency, and durability. Our goal is to establish a forward-looking roadmap that defines the role of hybrid photocatalysts as a transformative platform in achieving a sustainable, carbon-neutral society.