Synthesis of novel Co_xMo_(1-x)S-Cd_(0.5)Zn_(0.5)S composites with significantly improved photocatalytic hydrogen evolution performance under visible-light illumination

摘要

Recently, MoS2 incorporates with Co2+ (or Ni2+) was found to increase the photocatalytic performance of semiconducting materials more effectively. In this study, novel CoxMo1-xS was effectively deposited on the surface of Zn0.5Cd0.5S semiconductors as an efficient promotor using in-situ hydrothermal process. The as-prepared CoxMo1-xS-Zn0.5Cd0.5S composites are examined by the following techniques: XRD, TEM, DRS, XPS, PL and TRPL. The photocatalytic hydrogen evolution performance under visible illumination over Zn0.5Cd0.5S is remarkably increased by adding cheap CoxMo1-xS as promotor. The CoxMo1-xS-Zn0.5Cd0.5S hybrid specimen with 10% molar amount illustrates the best catalytic performance with a homologous hydrogen generation rate of 188.65 mu mol h(-1), which is estimated to be 14.5 folds than that of unmodified Zn0.5Cd0.5S specimen in the presence of visible light. The apparent quantum yield of Co0.3Mo0.7-Zn0.5Cd0.5S sample is determined to be 16.72% at monochromatic light of 420 nm. The experimental outcomes indicate that the synergistic action between CoxMo1-xS and Zn0.5Cd0.5S obviously promotes transfer of photo-induced charge carriers in the hybrid sample. A reasonable catalytic mechanism for the increased photocatalytic performance of CoxMo1-xS promotor was presented and authenticated by TRPL measure, which would present a new notion for the design of ideal semiconductors with plummy photocatalytic capability. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.