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

Abstract

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.