3DOM N/TiO 2 composite modified by CdS QDs with Z-scheme: enhanced photocatalytic degradation and hydrogen evolution

3DOM CdS QDs-N/TiO 2 composite was synthesized by CdS quantum dots (QDs) modified on the surface of 3DOM N/TiO 2 , of which the main component is anatase TiO 2 . The crystallinity of TiO 2 is improved by using polystyrene (PS) colloidal microspheres as the template. The introduction of CdS QDs not only expands the light absorption range of 3DOM N/TiO 2 , but also a Z-scheme heterojunction optimizing the charge transfer is formed. The results of photoluminescence spectroscopy and electrochemical impedance show that the lifetime of photogenerated charge carrier is prolonged in the composite 3DOM CdS QDs-N/TiO 2 , and the recombination of photogenerated electron–hole pairs is suppressed effectively. Compared with the main catalyst TiO 2 , the photocatalytic activity of 3DOM CdS QDs-N/TiO 2 is significantly enhanced. In the photohydrogen production experiment, the photohydrogen production capacity of 3DOM CdS QDs-N/TiO 2 composite material (2247 μmol·g −1 , 8 h) is 172.8 times that of the commercially available P25. After using 2.0 wt% Pt as a co-catalyst, the amount of hydrogen evolution (16,663 μmol·g −1 , 8 h) increases ca. 7.4 times. Through capture experiments, the possible photocatalytic reaction mechanism and the reason for the enhanced photocatalytic performance were speculated and discussed. Graphical abstract Using polystyrene colloidal microspheres as the template, a three-dimensional ordered macroporous composite 3DOM CdS QDs-N/TiO 2 was synthesized by vacuum impregnation and hydrothermal deposition. The quantum effect of CdS QDs, the unique 3DOM structure and the synergy between the Z-type heterojunction further increase the light absorption range of 3DOM CdS QDs-N/TiO 2 , which show the better perform of multi-mode photocatalytic degradation and photocatalytic hydrogen evolution.