Microwave-assisted synthesis of novel imine-linked copper porphyrin conjugated microporous polymers as heterogeneous photocatalysts

Conjugated microporous polymers (CMPs) have attracted increasing research interest as novel promising photocatalysts. Herein, microwave-assisted organic synthesis was carried out to prepare three types of imine-linked copper porphyrin-based CMPs (CuTAPP-CMPs), named as CuTAPP-CMP-OH, CuTAPP-CMP-OCH3, and CuTAPP-CMP-O(CH2)(3)CH3, respectively. The CuTAPP-CMPs have narrow bandgaps (1.97, 1.92 and 1.95 eV) with large surface areas, which could be used as heterogeneous photocatalysts under visible light. All CuTAPP-CMP-OH, CuTAPP-CMP-OCH3, and CuTAPP-CMP-O(CH2)(3)CH3 have excellent photocatalytic performances for model dyeRhodamine B (RhB, 3 h, degraded 98, 94 and 81%) degradation under visible-light irradiation. Among them, CuTAPP-CMP-OH exhibited high photocatalytic efficiency, which attributes to its better dispersion in water, more negative conduction band (CB) value and narrow bandgap inducing excellent photocurrent-response, thus indicating that the organic building block with different hydrophilic or hydrophobic group has great effect on the photocatalytic properties of the material. Moreover, CuTAPP-CMP-OH featured good recyclability and wide suitability. Therefore, our results provide a promising molecular design strategy of CMPs through a simple and efficient approach for the best performance of photocatalysis.