ZnxCd1–xS quantum dot with enhanced photocatalytic H2-production performance

Abstract

H2 is an important energy carrier for replacing fossil fuel in the future due to its high energy density and environmental friendliness. As a sustainable H2-generation method, photocatalytic H2 production by water splitting has attracted much interest. Here, oil-soluble ZnxCd1–xS quantum dot (ZCS QD) with a uniform particle size distribution were prepared by a hot-injection method. However, no photocatalytic H2-production activity was observed for the oil-soluble ZCS QD due to its hydrophobicity. Thus, the oil-soluble ZCS QD was converted into a water-soluble ZCS QD by a ligand-exchange method. The water-soluble ZCS QD exhibited excellent photocatalytic H2-production performance in the presence of glycerin and Ni2+, with an apparent quantum efficiency of 15.9% under irradiation of 420 nm light. Further, the photocatalytic H2-generation activity of the ZCS QD was ∼10.7 times higher than that of the ZnxCd1–xS relative samples prepared by the conventional co-precipitation method. This work will inspire the design and fabrication of other semiconductor QD photocatalysts because QD exhibits excellent separation efficiency for photogenerated electron–hole pairs due to its small crystallite size.