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

H-2 is an important energy carrier for replacing fossil fuel in the future due to its high energy density and environmental friendliness. As a sustainable H-2-generation method, photocatalytic H-2 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 H-2-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 H-2-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 H-2-generation activity of the ZCS QD was similar to 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. (C) 2021, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.