Hollow nanosphere conjugated microporous polymers with ultra-high photocatalytic degradation property of cationic dyes

Herein, two kinds of conjugated microporous polymers (CMPs) containing phenolic hydroxyl groups, CMP-OH1 and CMP-OH2, were prepared by Sonogashira−Hagihara coupling reaction, which were used as metal-free organic photocatalysts for photocatalytic degradation of cationic organic dyes. The hollow nanosphere had abundant surface defect sites that facilitated the separation of photogenerated electron-hole pairs, which enhanced the photocatalytic activity of CMP-OH1. Under visible light irradiation, the CMP-OH1 degradation efficiency for Methylene blue (MB) reached 99.5 % within 60 min, while the degradation efficiency for Rhodamine B (RhB) attained 99.9 % within 30 min. After 5 cycles, the degradation rate of cationic organic dyes by CMP-OH1 exceeded 92 %. Notably, the photocatalytic mechanism of CMP-OH1 has been examined that superoxide anion radical (·O2−) is the principal active substance produced in the photocatalytic degradation of cationic organic dyes. This work opens up a new way of treating dye-contaminated water with hollow nanosphere CMPs containing phenolic hydroxyl groups.