Electrospinning directly synthesis of 0D/1D CuBi2O4@WO3 nanofiber photocatalyst with S-scheme heterojunction

Abstract

A novel 0D/1D CuBi2O4@WO3 nanofiber-membrane photocatalyst with step-scheme (S-scheme) heterojunction was fabricated by means of the electrospinning method. The disintegration of CuBi2O4 microspheres under a high voltage electrospinning process led to the simultaneous formation of CuBi2O4 nanoparticles on WO3 nanofibers, therefore constructing well dispersed CuBi2O4@WO3 nano-heterojunctions. The CuBi2O4@WO3 composite photocatalyst followed the S-scheme charge transfer mechanism, which promoted the efficient charge transfer across the interface, thereby solving the problem that the narrow-bandgap CuBi2O4 had strong light-harvesting ability but easy recombination of photo-generated carriers. Moreover, such S-scheme heterojunction also achieved the spatial separation of photo-induced electrons and holes while ensuring the promising redox abilities in both WO3 and CuBi2O4. Hence, the CuBi2O4@WO3 composite photocatalyst exhibited excellent photocatalytic activity for photocatalytic degradation of antibiotics in environmental remediation under weak-visible-light irradiation (5 W LED lamp), and its photocatalytic activity for tetracycline degradation was significantly improved, which was 8.1 times and 3.6 times than that of WO3 nanofibers and pure CuBi2O4 microspheres, respectively. The radical species trapping tests indicated that·O2− and h+ were the main active radicals in the tetracycline photodegradation reaction, and the high-performance liquid chromatography-mass spectrometry test clarified three possible degradation reaction pathways of tetracycline. This work presented a facile method to fabricate 0D/1D CuBi2O4@WO3 composite nanofiber photocatalyst with well-dispersed CuBi2O4@WO3 nano-heterojunctions, and also provided a new idea for the preparation of new nanocomposite photocatalyst based on electrospinning process.