Fabrication of PVDF/TiO2@CQDs photocatalytic films by ink-jet printing for dye degradation under visible light

PVDF/TiO 2 @CQDs hybrid photocatalytic thin films were prepared by ink-jet printing. The printing ink was prepared with the TiO 2 , TiO 2 (s)@CQDs (surface composite), and TiO 2 (i)@CQDs (situ doping) nanoparticles as precursors, respectively. Compared to TiO 2 (s)@CQDs, TiO 2 (i)@CQDs has a smaller particle size (about 10.01 nm) and a narrower particle size distribution (6∼14 nm), which can improve the photocatalytic effect while avoiding nozzle clogging. The PVDF/TiO 2 (i)@CQDs hybrid film exhibited a high degradation efficiency ( η ) of 93.71 % for Rhodamine B (RhB) within 150 min under visible light with a catalyst load of only 0.49 wt%. The reaction rate constant ( ks ) of the PVDF/TiO 2 (i)@CQDs film was about 4.3 times higher than that of the PVDF/TiO 2 (s)@CQDs film. The small particle size of this S-scheme TiO 2 (i)@CQDs heterostructure nanoparticle and the more effective contact interface formed between TiO 2 and carbon quantum dots (CQDs) further facilitated electron transfer and enhanced photoactivity. The firmly immobilized catalysts on the Polyvinylidene fluoride (PVDF) film substrate through Ti-F coordination bonds ensured the reusability and stability of the photocatalytic film (the η of RhB still reached 88.05 % after 10 consecutive cycles). This work provides a new strategy for the application of ink-jet printing technology in photocatalysis.