Dye-sensitized oxide nanosheet photocatalysts for solar hydrogen evolution

Abstract Visible-light-driven H2 evolution using dye-sensitized photocatalysts has attracted considerable attention as a molecularly tunable approach for solar fuel generation. Among various semiconductor platforms, metal oxide nanosheets derived from their host layered materials provide unique opportunities because of their atomically thin crystalline structures, anisotropic carrier transport properties, large surface areas, and highly tailorable interfacial chemistry. In this Account, we summarize our research on dye-sensitized H2-evolving photocatalysts based mainly on niobate nanosheets, with particular emphasis on the interplay between nanosheet structure, interfacial electron transfer, and photocatalytic function. Early studies demonstrated that exfoliated oxide nanosheets and nanoscrolls efficiently mediate visible-light-induced electron injection from Ru(II) sensitizers, enabling H2 evolution even without covalent dye anchoring. Subsequent work revealed how nanosheet composition/crystallinity, cocatalyst deposition and dye structure govern charge separation and back electron transfer. More recent studies have established artificial Z-scheme systems for solar-driven overall water splitting and clarified excited-carrier dynamics through spectroscopic investigations. These findings highlight oxide nanosheets as versatile platforms for constructing highly organized hybrid photocatalysts and provide design principles for future solar-to-hydrogen conversion systems utilizing molecular–solid interfaces.