Co-MOF-67 derived hollow double-shell core Co3O4 with Zn0.5Cd0.5S to construct p-n heterojunction for efficient photocatalytic hydrogen evolution.

ABSTRACT

It is an effective way to improve the photocatalytic hydrogen evolution activity by constructing a unique structure and tuning the morphology of catalysts. On the one hand, ZIF-67 was used as a precursor to prepare Co3O4 derivatives with different morphologies [Co3O4 (Porous Polyhedron) and Co3O4db (Hollow Double-Shelled Polyhedron)]. The hollow polyhedron have the advantages of large specifie surface area, low density, stable three-dimensional spatial structure and excellent electron transport channels, which provide great advantages for the enhancement of photocatalytic activity in photocatalytic reactions. On the flip side, p-type Co3O4 polyhedron and n-type Zn0.5Cd0.5S nanoparticles are successfully coupled to construct a p-n heterojunction, which accelerated the transfer and separation of electrons and holes, thus enhancing the photocatalytic hydrogen production efficiency. Therefore, the composite catalyst (Zn0.5Cd0.5S-Co3O4db-20 %) exhibits excellent hydrogen evolution activity (33885 µmol·h-1·g-1), which is 9.17 times that of pure Zn0.5Cd0.5S (3695 µmol·h-1·g-1) and 1.21 times that of Zn0.5Cd0.5S-Co3O4-20 % (27903 µmol·h-1·g-1). This work provides a new idea for tuning the photocatalytic morphology to enhance the hydrogen evolution activity.