Highly efficient photocatalytic antifouling activity of core-shell structural encapsulation Bi2MoO6 with visible-light responsive ZIF-67

Abstract

In this work, novel Bi2MoO6/ZIF-67 S-scheme heterojunctions with core-shell structures were fabricated via in-situ enwrapping ZIF-67 nanocubes on Bi2MoO6 flower-like microspheres, which were applied in photocatalytic antifouling towards typical marine bacteria and microalgae. Experimental results indicated that Bi2MoO6/ZIF-67 displayed excellent and stable photocatalytic performances against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) under visible light irradiation, and almost all S. aureus and E. coli can be killed within 40 min and 50 min, respectively. Similarly, Bi2MoO6/ZIF-67 exhibited remarkable photocatalytic properties in removing microalgae, achieving the removal efficiencies of 96.0% and 84.4% towards Phaeodactylum tricornutum (P. tricornutum) and Chlorella sp. within 6 h, respectively. The introduction of ZIF-67 obviously improved the specific surface area and photoabsorption ability of Bi2MoO6, combined with the formation of S-scheme heterojunction with core-shell structure, highly enhancing the photocatalytic antifouling activity of Bi2MoO6/ZIF-67. Moreover, a possible photocatalytic mechanism was proposed, validating that h+, OH, O2–, and 1O2 played crucial roles during the photocatalytic process. The transfer direction of photoelectrons and band structures in Bi2MoO6/ZIF-67 were further verified by the density functional theory (DFT) simulated calculations, confirming the formation of S-scheme heterojunction and fast separation efficiency of photoinduced charge carriers. Furthermore, Bi2MoO6/ZIF-67 S-scheme heterojunctions were coated on dacromet and placed in actual marine environment, showing a favorable antifouling performance with fewer living microorganisms attached. This work not only provides new insights in developing novel heterojunctions with highly efficient photocatalytic activities, but also presents a promising application prospect for photocatalysts in the field of marine antifouling.