Complementary metalloporphyrin-based nanostructure decorated with silver nanoparticles for photocatalytic degradation of organic dyes

Abstract

A hybrid composite photocatalyst, SA-T@Ag, was fabricated by the photoreduction of silver salts in the presence of nanomaterials composed of self-assembled complementary porphyrin triad SA-T. We confirmed the formation of SA-T@Ag from SA-T using various spectroscopic techniques, including X-ray diffraction (XRD), infrared (IR) spectroscopy, UV–visible spectroscopy, and fluorescence spectroscopy. Field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) investigations revealed that a substantial amount of silver nanoparticles (AgNPs) were deposited on the surface of SA-T and that the microstructure of SA-T was intact during photoreduction. The formation of AgNPs on the surface of SA-T reduced the band gap energy (Eg) of SA-T@Ag compared to that of SA-T. This not only improves its light-harvesting properties but also delays the recombination of photogenerated electron-hole pairs, which promotes more reactivity under visible light irradiation and improves the efficiency of polluted dye degradation. These photophysical properties are reflected in the degradation of methylene blue (MB) dye under visible light irradiation. The first-order degradation rate constant of MB dye within 45 min of visible light irradiation is much higher for SA-T@Ag (0.081 min−1) than SA-T (0.028 min−1). This report is of great importance in the field of environmental remediation and provides new opportunities for designing porphyrin-based photocatalytic systems as alternatives to conventional photocatalysts.