S-Scheme Ti@Ce MOF Heterojunction for Enhanced Visible-light Photocatalytic Degradation

Solar photocatalytic degradation and adsorption using metalorganic frameworks (MOFs) offer safe and energy-efficient remediation for water contaminated with small organic pollutants, leveraging their semiconductor-like tunable band structures and inherent porosity. This study reports the de novo synthesis of a visible-light-responsive Ti@Ce MOF heterojunction composite for synergistic photocatalytic degradation and adsorption of recalcitrant organic contaminants. An in-situ growth strategy deposited NO.-functionalized UiO-66(Ce) onto NH 2 -modified MIL-125, forming an S-scheme heterojunction engineered for efficient visible-light-driven hydrogen peroxide (H 2 O 2 ) generation. This in-situ photogenerated H 2 O 2 acts as a potent oxidant, effectively degrading tetracycline. A significantly enhanced photocatalytic degradation rate constant ( k ) for tetracycline was observed, indicating boosted catalytic activity. Mechanistic analysis underscores the critical role of the S-scheme heterojunction in promoting charge carrier separation and enhancing H 2 O 2 production, thereby efficiently driving organic pollutant oxidative degradation. This work provides a novel strategic framework for designing multifunctional MOF composites, advancing high-performance, sustainable water purification technologies.