Hollow Core-Shell potassium Phosphomolybdate@Cadmium Sulfide@Bismuth sulfide Z-Scheme tandem heterojunctions toward optimized Photothermal-Photocatalytic performance

A hollow core–shell potassium phosphomolybdate (KMoP)@cadmium sulfide (CdS)@bismuth sulfide (Bi 2 S 3 ) Z-scheme tandem heterojunction is fabricated by a simple hydrothermal strategy and kept in a water bath to continue the reaction. At the same time, the ternary structure combined Keggin-type polyoxometalate with two photosensitive sulfide semiconductors to form a stable hollow core–shell heterojunction. KMoP@CdS@Bi 2 S 3 with a narrow band gap of ∼ 1.2 eV also has excellent photothermal performance, which may further promote photocatalytic efficiency. The hollow core–shell KMoP@CdS@Bi 2 S 3 tandem heterojunction shows excellent H 2 production performance, Cr VI reduction ability and photocatalytic degradation performance of highly toxic tetracycline (TC). Under visible light irradiation , the photocatalytic H 2 generation rate of the KMoP@CdS@Bi 2 S 3 tandem heterojunction reaches 831 μmol h −1 , which is 103 times higher than that of pristine KMoP. The photocatalytic reduction efficiency of Cr VI and degradation efficiency of TC are as high as 95.5 and 97.51%, ∼4 times higher than that of KMoP. The boosted photocatalytic performance can be ascribed to the formation of core–shell Z-scheme tandem heterojunctions favoring spatial charge separation and the narrow band gap, which extends the photoresponse to visible light/NIR regions. When TC and Cr VI exist at the same time, the reduction efficiency of Cr VI can be as high as 99.64% because the intermediate of TC degradation can promote the reduction of Cr VI . In addition, the photocatalytic performance of the KMoP@CdS@Bi 2 S 3 heterojunction remains nearly constant after 4 recycles, which indicates high stability. The design strategy may provide new insights for preparing other high-performance core–shell tandem heterojunction photocatalysts for solar energy conversion .