Formation of double-shelled hollow spherical CdS/Ca0.3Zn2.7In2S6 as S-scheme photocatalysts for highly efficient photocatalytic hydrogen evolution

While the configuration of most metal oxides hollow structures is well established, the synthesis of multinary metal sulfides with complex multi-shelled hollow structures remains in its infancy. Herein, we have developed a facile method to synthesize superhydrophilic Ca0.3Zn2.7In2S6 double-shelled hollow structures (DSHSs) with the assistance of trisodium citrate bilamellar vesicles, which manifests higher photocatalytic hydrogen generation rate compared with normal Ca0.3Zn2.7In2S6 single-shelled hollow structures and solid microflowers. Further construction of CdS/Ca0.3Zn2.7In2S6 S-scheme heterostructures by in situ photodeposition of CdS ultrafine nanoparticles on Ca0.3Zn2.7In2S6 DSHSs creates an intimate interface coupling and expansive contact region for fast interfacial charge transfer. Consequently, CdS/Ca0.3Zn2.7In2S6-5.0 composite exhibits a boosted photo- catalytic H2 evolution of 30.08 mmol h- 1 g-1, which is 2.7 times higher than Ca0.3Zn2.7In2S6 DSHSs (11.52 mmol h- 1 g-1). Besides, the apparent quantum efficiency of CdS/Ca0.3Zn2.7In2S6-5.0 at 370 nm can reach 66.04 %. Moreover, CdS/Ca0.3Zn2.7In2S6-5.0 shows good stability for the hydrogen generation reaction. This elaborate design of CdS/Ca0.3Zn2.7In2S6-5.0 sheds light on the potential of integrating morphology modulation and S scheme heterostructures construction with efficient solar energy utilization and optimized charge transfer for catalysis and optoelectronic applications.