A hollow core–shell potassium phosphomolybdate (KMoP)@cadmium sulfide (CdS)@bismuth sulfide (Bi₂S₃) 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@Bi₂S₃ 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@Bi₂S₃ tandem heterojunction shows excellent H₂ production performance, Cr^VI reduction ability and photocatalytic degradation performance of highly toxic tetracycline (TC). Under visible light irradiation, the photocatalytic H₂ generation rate of the KMoP@CdS@Bi₂S₃ 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@Bi₂S₃ 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.

空心核壳磷钼酸钾（KMoP）@硫化镉（CdS）@硫化铋（Bi ₂ S ₃）Z型串联异质结是通过简单的水热策略制造的，并保持在水浴中以继续反应。同时，三元结构将 Keggin 型多金属氧酸盐与两种光敏硫化物半导体结合，形成稳定的空心核壳异质结。KMoP@CdS@Bi ₂ S ₃具有~1.2 eV的窄带隙也具有优异的光热性能，可以进一步提高光催化效率。空心核壳 KMoP@CdS@Bi ₂ S ₃串联异质结显示出优异的 H ₂生产性能，Cr剧毒四环素（TC）的^VI还原能力和光催化降解性能。在可见光照射下，KMoP@CdS@Bi ₂ S ₃串联异质结的光催化H ₂生成率达到831 μmol h ^-1，是原始KMoP的103倍。Cr ^VI的光催化还原效率和 TC 的降解效率分别高达 95.5% 和 97.51%，是 KMoP 的 4 倍。光催化性能的提高可归因于核壳 Z 型串联异质结的形成，有利于空间电荷分离和窄带隙，将光响应扩展到可见光/近红外区域。当 TC 和 Cr^VI同时存在，Cr的还原效率^VI可高达99.64％，因为中间TC降解的可促进Cr的还原^VI。此外，KMoP@CdS@Bi ₂ S ₃异质结的光催化性能在4次循环后几乎保持不变，表明其具有高稳定性。该设计策略可能为制备用于太阳能转换的其他高性能核壳串联异质结光催化剂提供新的见解。