Enhanced visible light photocatalytic activity of alkaline earth metal ions-doped CdSe/rGO photocatalysts synthesized by hydrothermal method

Quantum dots (QDs) CdSe exhibits relatively high photocatalytic abilities for its unique properties, but the aggregation and photocorrosion have blocked its further application. Therefore, for arriving at a solution, alkaline earth metal ions (M=Mg²⁺, Ca²⁺, Sr²⁺ and Ba²⁺) and reduced graphene oxide (rGO) are chosen to fabricated new QDs CdSe-based photocatalytic systems. In this paper, M@CdSe/rGO composites have been synthesized via a facile one-step hydrothermal approach, during which the formation of M doped CdSe crystallization and GO reduction occur simultaneously. The obtained photocatalysts demonstrates synergistically enhanced visible light photocatalytic activity and stability toward photodegrading tetracycline hydrochloride (TC-HCl) solution, especially the introduction of 6mol% Ca²⁺ and 5wt% GO on QDs CdSe resulted in 85.6% degradation of 15mg/L TC-HCl in 1h with 0.5g/L catalyst. Furthermore, the photodegradation mechanism was systematically investigated by active species trapping experiment. It revealed that h⁺ was the major active species in the destructions process. And the possible process of charge transfer for Ca²⁺@CdSe/rGO nanocomposite was proposed based on the experimental results.