Synthesis of transition metal ions doped-ZrO2 nanoparticles supported g-C3N4 hybrids for solar light-induced photocatalytic removal of methyl orange and tetracycline pollutants

Photodegradation is an eco-friendly degradation process routinely employed for the removal of various pollutants produced by pharmaceutical and textile industries. In this work, g-C3N4 sheets (g-CN) supported with Fe-doped ZrO2 nanoparticles have been prepared via a facile hydrothermal method as photocatalysts for the effective photodegradation of methyl orange (MO) and tetracycline (TC). The as-prepared photocatalysts were characterized by using a wide range of techniques to understand the origin of their superior photodegradation performance. Structurally, Fe-doped ZrO2 nanoparticles were found to be uniformly superficially distributed on g-C3N4. The addition of Fe-doped ZrO2 nanoparticles was also found to improve the surface area and light absorption capacity of pure g-CN. It was further revealed that the development of heterojunctions between g-C3N4 and Fe-doped ZrO2 nanoparticles effectively reduced the recombination rate of electron and hole pairs within the photocatalyst system, resulting in improved photocatalytic activity. Previous studies have pointed at the superoxide radical anions (˙O2-) and (OH·) as being primarily responsible for the degradation of MO and TC species, leading us to hypothesize that the g-FZ composite works via a possible free-radical based catalytic mechanism to support the photodegradation process.