Sequential Chemistry Toward Core?Shell Structured Metal Sulfides as Stable and Highly Efficient Visible-Light Photocatalysts

Abstract

A universal sequential synthesis strategy in aqueous solution is presented for highly uniform core–shell structured photocatalysts, which consist of a metal sulfide light absorber core and a metal sulfide co-catalyst shell. We show that the sequential chemistry can drive the formation of unique core–shell structures controlled by the constant of solubility product of metal sulfides. A variety of metal sulfide core–shell structures have been demonstrated, including CdS@CoSx, CdS@MnSx, CdS@NiSx, CdS@ZnSx, CuS@CdS, and more complexed CdS@ZnSx@CoSx. The obtained strawberry-like CdS@CoSx core–shell structures exhibit a high photocatalytic H2 production activity of 3.92 mmol h−1 and an impressive apparent quantum efficiency of 67.3 % at 420 nm, which is much better than that of pure CdS nanoballs (0.28 mmol h−1), CdS/CoSx composites (0.57 mmol h−1), and 5 %wt Pt-loaded CdS photocatalysts (1.84 mmol h−1).