Ternary Co3O4/CdS/SrTiO3 core-shell pn junctions toward enhanced photocatalytic hydrogen production activity

A ternary Co3O4/CdS/SrTiO3 core-shell pn junction is fabricated via a simple hydrothermal-chemicalphotodeposition method. Herein, a CdS shell is deposited on the surface of a SrTiO3 nanosphere, and then ptype Co3O4 lamellas are grown on the surface of the CdS/SrTiO3 core-shell heterojunction. Evaluated by its hydrogen evolution ability, the as-prepared ternary Co3O4/CdS/SrTiO3 core-shell pn junction exhibits an obvious photocatalytic enhancement of similar to 15-fold compared to single SrTiO3 nanospheres. This improvement can be mainly ascribed to the narrow band gaps of CdS and Co3O4 increasing the visible light response, and the ternary core-shell pn junction quickly transferring/diffusing photogenerated charge carriers into water. Additionally, the core-shell structure can provide sufficient active sites, and the ultrathin Co3O4 lamellas can shorten the photoelectron transport path to improve the photocatalytic stability.