Unfading TiO2 Photocatalyst Star Materials: Scandium Doping for Enhanced Photocatalytic Overall Water Splitting

• • Scandium doping at 5% via molten salt synthesis reduces deep-level Ti3+ defect concentration in rutile TiO2, directly suppressing non-radiative charge recombination and boosting quantum efficiency beyond the typical <2% ceiling under ambient conditions without sacrificial agents. • • The Sc3+ dopant induces a robust built-in electric field that provides sufficient thermodynamic driving force for directional electron-hole migration, overcoming the weak internal fields that plague undoped and Al-doped TiO2, thereby enhancing charge separation efficiency. • • Comparative analysis with undoped and aluminum-doped TiO2 demonstrates that Sc doping uniquely minimizes deep-trap states while maintaining photochemical stability, achieving marked enhancement in hydrogen generation rates from water under sunlight. • • The molten salt method enables homogeneous incorporation of Sc atoms into the rutile lattice, offering a scalable synthesis route that could reduce reliance on costly noble metals and advance Earth-abundant photocatalytic OWS systems for industrial green hydrogen production.