Photocatalytic degradation of tetracycline hydrochloride with visible light-responsive bismuth tungstate/conjugated microporous polymer

Conjugated microporous polymer (CMP) is an emerging organic semiconductor with π-conjugated skeletons, and the bandgap of CMP can be flexibly modulated to harvest visible light. Based on the diversity and adjustability of monomers in CMP, we designed and synthesized donor-accepter (D-A) type BTN-CMP through Sonogashira-Hagihara cross-coupling polymerization, further in-situ constructing series of inorganic/organic Z-scheme BW/BTN-n composite in the presence of Bi2WO6. After optimization, the tetracycline hydrochloride (C0 = 10 mg·L−1) degradation efficiency reached 84% with BW/BTN-2 as catalyst in 90 min under visible light irradiation, the apparent rate constant k1 is 0.017 min−1, which is 1.7 and 5.7 times higher than bare Bi2WO6 and BTN-CMP. X-ray photoelectron spectra and UV–Vis diffuse spectra showed that the enhanced photocatalytic activity originated from the tight heterojunction between Bi2WO6 and BTN-CMP, which can extend the light absorption range and facilitate the separation and transport of photogenerated charges in the interface of heterojunction. The active species trapping experiments and electron spin resonance technique revealed that h+ was the dominant active species during the photodegradation process of tetracycline hydrochloride (TCH). The present study demonstrated the feasibility to construct inorganic/organic composite for the photocatalytic degradation of environmental pollutants.