3.1 Synthesis of CoP/ZnCdS/Co3O4QDs
Herein, we demonstrate the rational design and construction of hierarchical CoP/ZnCdS/Co3O4QDs bi-heterostructure cages by assembling about 800 nm CoP polyhedrons, 40 nm ZnCdS, and 4.5 nm Co3O4 QDs as a prominent photocatalyst for H2 evolution. The overall synthetic route for constructing the delicate architectures is schematically illustrated in Fig. 1. Starting with ZIF-67 dodecahedrons as the precursor, CoP polyhedrons with large surface was gained via phosphatizing reaction. In addition, ZnCdS nanoparticles and Co3O4 QDs are synthesized via solvothermal methods. Finally, the two cages, CoP/ZnCdS heterostructure cage with 40 nm ZnCdS nanoparticles coated on the surface of about 800 nm CoP polyhedron and ZnCdS/Co3O4 QDs cages with 4.5 nm Co3O4 QDs decorated on the surface of 40 nm ZnCdS nanoparticle, are integrated into all-in-one hierarchical CoP/ZnCdS/Co3O4QDs bi-heterostructure cages via utilizing their pyramid-shaped size distribution. The complex CoP/ZnCdS/Co3O4 QDs bi-heterostructure cage architectures with excellent metal phosphide, solid solution, and quantum dot subunits can seriously accelerate the separation and transfer of electron-hole pairs, offer large surface area, and expose a lot of active sites for photocatalytic H2 production. Accordingly, the optimum CoP/ZnCdS/Co3O4QDs bi-heterostructure cages reveal ultrahigh activity and high stability for visible light driven water splitting.