Search

Synthesizing novel photocatalysts that can effectively harvest photon energy over a wide range of the solar spectrum for practical applications is vital. Porphyrin-derived nanostructures with properties similar to those of chlorophyll have emerged as promising candidates to meet this requirement. In this study, tetrakis(4-carboxyphenyl) porphyrin (TCPP) nanofibers were formed on the surface of ZnO nanoparticles using a simple self-assembly approach. The obtained ZnO/TCPP nanofiber composites were characterized via scanning electron microscopy, X-ray diffraction analysis, and ultraviolet–visible absorbance and reflectance measurements. The results demonstrated that the ZnO nanoparticles with an average size of approximately 37 nm were well integrated in the TCPP nanofiber matrix. The resultant composite showed photocatalytic activity of ZnO and TCPP nanofibers concomitantly, with band gap energies of 3.12 and 2.43 eV, respectively. The ZnO/TCPP photocatalyst exhibited remarkable photocatalytic performance for RhB degradation with a removal percentage of 97% after 180 min of irradiation under simulated sunlight because of the synergetic activity of ZnO and TCPP nanofibers. The dominant active species participating in the photocatalytic reaction were •O2– and OH•, resulting in enhanced charge separation by exciton-coupled charge-transfer processes between the hybrid materials.

As a traditional direct bandgap oxide semiconductor, ZnO, showed as a promising photocatalytic candidate. Researchers worldwide reported many possibilities to improve its photocatalytic activity such as doped with metal, non-metal ions. As a result of heterojunction formation between ZnO and its intentional impurity, previous reports showed beneficial characteristics for enhancing photocatalytic activity in these ZnO-based materials, i.e. bandgap narrowing, recombination rate of photoelectron-hole prolonging, visible light absorption improving. This work will present the photocatalytic acitivity improvement of ZnO when doping with ion Cu2+ and try to illustrate the crucial photocatalytic enhancement factors.