Shell Thickness Engineering Significantly Boosts the Photocatalytic H2 Evolution Efficiency of CdS/CdSe Core/Shell Quantum Dots

Colloidal semiconductor quantum dots (QDs) have recently emerged as a good candidate for photocatalytic hydrogen (H2) evolution in water. A further understanding of the factors that can affect and boost the catalytic activity of the QD-based H2-generating system is of great importance for the future design of such systems for practical use. Here, we report on the fine shell thickness engineering of colloidal CdS/CdSe core/shell QDs and its effect on the photocatalytic H2 production in water. Our results show that, with the proper shell thickness, the H2 photogeneration quantum yield (ΦH2) of CdS/CdSe core/shell QDs could reach 30.9% under the illumination of 420 nm light, which is 49% larger than that of the CdS core. Furthermore, the underlying mechanism has also been tentatively proposed and discussed.