Organic-inorganic TCPP/BiOCl hybrids with accelerated interfacial charge separation for boosted photocatalytic performance

High interfacial separation efficiency of photoinduced electron-hole pairs and wide visible light spectral response are the two crucial factors for the improvement of photocatalytic performance in photocatalysis technology. In this research, a new 2D/3D organic-inorganic hybrid (TCPP/BiOCl) was constructed by combing 2D rod-shaped meso-tetra(4-carboxyphenyl) porphyrin (TCPP) with 3D hierarchical flower-like BiOCl by a solvothermal in-situ growth method. The introduction of macrocyclic TCPP largely expanded visible light absorption of BiOCl and boosted the separation of photoinduced charge carriers. Consequently, compared to pure BiOCl, TCPP/BiOCl composites exhibited better photocatalytic performance on the degradation of broad-spectrum antibiotics including tetracycline (TC), ciprofloxacin (CIP) and enrofloxacin (ENR) under visible light irradiation, and the optimal mass ratio of TCPP was determined to be 1 wt%. Repeated cycling experiments proved the excellent stability of TCPP/BiOCl hybrids. The radicals trapping experiments and electron spin-resonance spectroscopy (ESR) tests confirmed the synergism of superoxide radical (O2−), hydroxyl radical (OH) and h+ during the photocatalytic degradation process. Finally, a conceivable photocatalytic mechanism was proposed to interpret the effective separation and transfer of photogenerated electron-hole pairs.