The high photocatalytic efficiency and stability of the Z-scheme CaTiO3/WS2 heterostructure for photocatalytic removal of 17α-ethinyl estradiol in aqueous solution

Abstract

In this study, a new Z-scheme CaTiO3/WS2 heterostructure composed of CaTiO3 nanoparticles and WS2 nanosheets was rationally constructed and successfully fabricated through a facile ultrasonication strategy, a continuous stirring process and a heat treatment method, successively. As expected, the resultant Z-scheme CaTiO3/WS2 heterostructure displayed drastically improved photocatalytic performance of 17α-ethinyl estradiol (EE2) degradation in an aqueous solution under UV-light irradiation. Significantly, the optimization of the Z-scheme CaTiO3(20 wt%)/WS2 heterostructure revealed prominent photocatalytic activity for EE2 degradation rate up to 0.0024 min−1 under UV-light irradiation, which was about 12 and 4 times larger than those of pure WS2 and pristine CaTiO3, respectively. The Z-scheme CaTiO3(20 wt%)/WS2 heterostructure achieved the highest photodegradation rate of more than 96 % for EE2 photodegradation in 120 min under visible light irradiation. The improved photocatalytic performance could be mainly ascribed to the formation of a direct Z-scheme LaNiO3/g-C3N4 heterojunction, which results in the interfacial charge transfer efficiency and the strong redox ability of the photogenerated electrons and holes. Additionally, the degradation mechanism of EE2 by active species trapping showed that the synergistic effect of superoxide radicals (•O2–) and holes were the main active species and were responsible for the photodegradation of EE2. This work will provide a new design approach to construct high-performance Z-scheme WS2-based composite photocatalysts for photocatalyst degradation of EE2 and environmental remediation.