Layered and poriferous (Al,C)-Ta2O5 mesocrystals supported CdS quantum dots for high-efficiency photodegradation of organic contaminants

• Layered and poriferous Ta 2 O 5 mesocrystals; • Elemental doping induced efficient charge separation; • S-scheme CdS QDs/(Al,C)-Ta 2 O 5 composites; • High-performance and mechanism. Preparation of high-performance composites photocatalysts for organic pollutants degradation is of great significance. In this work, elemental doping was employed to realize the visible-light harvesting and visible-light photocatalysis of the (Al,C)-Ta 2 O 5 mesocrystals following by introduction of CdS quantum dots (QDs) into layered and poriferous (Al,C)-Ta 2 O 5 nanosheets for fabrication of S-scheme charge transfer pathways. In this work, the higher temperatures treatment induced the successful transformation of (Al,C)-Ta 2 O 5 nanosheets from Ta 3 AlC 4 MAX. The experimental results also revealed that CdS QDs/(Al,C)-Ta 2 O 5 composites showed highly enhanced visible-light absorption and visible-light photocatalytic tetracycline degradation performance. The optimal photocatalytic reaction rate constant of the CdS QDs/(Al,C)-Ta 2 O 5 -30% composite reached as high as 0.1117 min −1 , which was approximately 27.24 times of the (Al,C)-Ta 2 O 5 nanosheets and 2.43 times of CdS QDs, far better than those of commercial Ta 2 O 5 and pristine Ta 3 AlC 4 . Meanwhile, the prepared CdS QDs/(Al,C)-Ta 2 O 5 composites were also employed for efficient photodegradation of norfloxacin. Besides, the effects of various experimental parameters, reactive species determination, and band structures were also investigated. The improved visible-light photocatalytic performance of the CdS QDs/(Al,C)-Ta 2 O 5 composites was mainly attributed to fabrication of S-scheme charge transfer pathways for efficient charge separation.