Microfluidic continuous flow production of Pt nanoparticles stabilized on Cu-TCPP@ MOFs for efficient photocatalytic degradation: mechanism and degradation pathways

Porphyrin-based metal–organic frameworks are widely utilized in the photocatalytic field owing to their unique photosensitive properties. Whereas controllable substrate morphology and uniform distribution of the noble metal nanoparticles still remain challenging in traditional synthesis. Herein, Cu-TCPP@MOFs and PtNPs/Cu-TCPP@MOFs with flower-like architecture were produced via continuous flow strategy and double spiral microreactor efficiently and controllably. The results revealed that 5.2 wt% Pt nanoparticles with 2.68 nm were embedded evenly on the Cu-TCPP@MOFs within 5 min. Compared to the Cu-TCPP@MOFs, the PtNPs/Cu-TCPP@MOFs exhibited much superior catalytic performance for rhodamine B (RhB) degradation under visible-light-driven, the reaction rate constant and catalytic activity parameter increased from 0.010 to 0.027 min −1 , and 0.03 to 11.25 s·g −1 , respectively. The free radical capture experiments revealed that h + , ·OH, and ·O 2 − played a synergistic role in the RhB degradation, whereas ·OH plays the most prominent effect. The reasonable degradation pathways of RhB were proposed by combining the density functional theory (DFT) with liquid chromatography mass spectrometry (LC-MS) investigation. This work not only provided insights into the design and controllable preparation of high-performance photocatalysts but also provided an effective strategy for degrading organic pollutants in the water environment, which poses significant environmental and economic benefits.