Synthesis of novel zinc porphyrins and their photocatalytic activity

Abstract

Purpose

The purpose of this study is to investigate the effect of the spacer length of zinc porphyrin-TiO₂ hybrids by photodegradation of methyl orange (MO) in aqueous solution under visible light.

Design/methodology/approach

5-Mono-[4-hydroxyphenyl]-10,15,20-triphenylporphyrin was synthesized using Alder method. A new series of porphyrins and their corresponding zinc complexes (ZnPp) were obtained from 5-mono-[4-hydroxyphenyl]-10,15,20-triphenylporphyrin via nucleophilic substitution reaction. The ZnPp-TiO₂ photocatalysts were prepared by loading ZnPp onto TiO₂ and characterized by scanning electron microscope, X-ray diffraction, UV-vis diffuse reflectance spectrum and X-ray photoelectron spectroscopy.

Findings

The results indicated that zinc porphyrins were successfully loaded on the surface of TiO₂ microsphere, which is crucial to enhance the activity of the catalytic composite under visible light. All the novel photocatalysts showed much enhanced photoactivity than bare TiO₂. Among all the prepared ZnPp-TiO₂, 5,10,15-triphenyl-20-[4-(4-naphthoxy)-butoxy]phenyl zinc porphyrin-TiO₂ (4b) showed the highest photocatalytic activity for the degradation of MO.

Research limitations/implications

Synthesis of these zinc porphyrins had never been reported previously.

Originality/value

Four novel zinc porphyrin-TiO₂ photocatalysts which could response to visible light in degradation of MO were synthesized using Alder method. The results show that the photocatalytic activity of 5,10,15-triphenyl-20-[4-(4-naphthoxy)butoxy] phenyl zinc porphyrin- TiO₂ is higher than others.

Citation

Chen, S.R. (2018), "Synthesis of novel zinc porphyrins and their photocatalytic activity", Pigment & Resin Technology, Vol. 47 No. 4, pp. 360-366. https://doi.org/10.1108/PRT-02-2017-0016