Carbon dots as electron acceptors modified NH2-MIL-125 (Ti)/Cu2O heterojunction for highly efficient photocatalytic H2 production

The development of high-efficiency photocatalysts for water splitting to hydrogen (H 2 ) is crucial for alleviating energy crisis and environmental problems. In this study, a novel type-II ternary heterojunction photocatalyst, CDs/NH 2 -MIL-125 (Ti)/Cu 2 O, was fabricated through the integration of NH 2 -MIL-125 (Ti) with Cu 2 O and carbon dots (CDs), exhibited excellent photocatalytic H 2 production rate of 12817.1 μmol/g/h with apparent quantum efficiency (AQE) of 17.13 % under visible light irradiation. Characterization revealed a uniform and dense structural integration with a high Brunauer-Emmett-Teller (BET) surface area of 275.9 m 2  g −1 and a suitable energy band gap of 2.18 eV. Furthermore, the heterostructures promoted efficient photo-generated carrier separation and enhanced reduction capabilities . Notably, CDs, serving as cocatalysts or electron acceptors, improved visible light utilization and electron migration, significantly boosting H 2 production. Insights from electron spin resonance (ESR) and density functional theory (DFT) calculations supported the migration mechanisms of electrons. This work presents a significant advance in photocatalytic technology for sustainable energy by designing high-performance CDs-modified heterojunction photocatalysts.