Novel in situ fabrication of conjugated microporous poly(benzothiadiazole)-Bi2MoO6 Z-scheme heterojunction with enhanced visible light photocatalytic activity

- Z-scheme BBT-BMO was fabricated by facile in situ cross-coupling polycondensation.
- BBT-BMO improves sulfathiazole photocatalytic degradation and Cr(VI) reduction.
- The photogenerated e−/h+ separation efficiency of BBT-BMO is greatly enhanced.
- The catalyst can work in a broad visible light region up to ∼700 nm.

A novel conjugated microporous poly(benzothiadiazole)-Bi2MoO6 (BBT-BMO) Z-scheme heterojunction was fabricated in situ through a facile palladium-catalyzed Sonogashira-Hagihara cross-coupling polycondensation of 4,7-dibromobenzo[c][1,2,5]thiadiazole and 1,3,5-triethynylbenzene on the surface of Bi2MoO6. Characterization results illuminated that BBT was stably coated on the surface of Bi2MoO6 nanosheets with the formation of CO bonds. This novel BBT-BMO composite exhibited superior photocatalytic performance in both sulfathiazole degradation and Cr(VI) reduction compared with pure BBT and Bi2MoO6 in visible light. In line with systematic characterizations results, a reasonable photocatalytic mechanism based on direct Z-scheme heterojunction was proposed and further verified via OH determination. This Z-scheme heterojunction endowed it with improved visible light absorption, larger surface area, and greater electron-hole separation and thus efficiently enhanced the photocatalytic performance. This work provides new insight into the utilization of conjugated microporous polymers in photocatalysis and paves a new way to construct Z-scheme heterojunctions with enhanced photocatalytic performance via metal-free polymers modification.

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