Oxygen vacancy-induced donor–acceptor-conjugated microporous poly(triphenylamine–benzothiadiazole)/TiO2 as a Z-scheme heterojunction photocatalyst towards a visible-light-driven degradation of bisphenol A

Abstract

Herein, a kind of donor–acceptor-conjugated microporous polymer (D–A CMP), poly(triphenylamine–benzothiadiazole) denoted as TPABT, was introduced to synthesize a novel organic–inorganic heterojunction photocatalyst with TiO₂ by in situ polycondensation. Resultant TPABT/TiO₂ composites were used to photodegrade bisphenol A (BPA) under visible light. Results indicated that the TPABT/TiO₂ composite with a mass ratio of TPABT to TiO₂ of 10 : 100 (labeled as 10-TPABT/TiO₂) showed optimum photocatalytic activity, 8 and 4 times that of pure TiO₂ and TPABT, respectively. Systematic characterizations revealed that the incorporation of TPABT caused the generation of oxygen vacancies on TiO₂, which improved the visible light responsiveness of TiO₂. Moreover, EIS (electrochemical impedance spectroscopy), photocurrent response and PL emission spectra suggested that 10-TPABT/TiO₂ composites exhibited optimum activity than TPABT and TiO₂. Moreover, detailed investigations indicated that the improvement in the photoactivity of TPABT/TiO₂ contributed to the formation of a Z-scheme heterojunction, which enhanced the charge transfer from TPABT to TiO₂. This work provides some interesting ideas for enhancing the photocatalytic activity of TiO₂ and exploiting efficient heterojunction photocatalysts based on CMPs for pollutant degradation.