Synthesis of Mg-doped PbMoO4 spinel for photocatalytic degradation of dye solutions (BB and BG dyes)

Abstract

This study introduces a novel Mg-doped PbMoO₄ spinel that is used for the photocatalytic degradation of dye solutions, specifically BB and BG dyes. The bare and Mg-doped PbMoO₄ were synthesized by co-precipitation method and their materials were analyzed by XRD, DRS, PL, FT-IR, SEM, HR-TEM, and XPS techniques to determine the structural, morphological, optical, and vibrational properties. The XRD outcomes display that bare and Mg (0.025–0.075 M)-doped PbMoO₄ possess a tetragonal system with no other phase step. DRS analysis affirmed that Mg doping alters the energy gaps of PbMoO₄ with increasing Mg content from 0.025 to 0.075 M, respectively. XPS and PL spectra revealed that Mg doping induced defect states or oxygen vacancies, which prevented charge carrier recombination. SEM and HR-TEM micrographs of Mg (0.050 M)-doped PbMoO₄ nanoparticles exhibit certain particles that are spherical with slight agglomeration. These particle sizes are determined around 25 nm. The photodegradation activity of bare and Mg-doped PbMoO₄ catalyst was assessed in the removal of BG and BB dye solutions under visible irradiation. The consequence of several parameters, including irradiation time, pH, catalyst dosage, COD and reactive species, on the photodegradation of BG and BB was examined. With Mg (0.050 M)-doped PbMoO₄ after 120 min irradiation, 99 and 95% of BG and BB removal was observed in pH = 7 conditions, while with bare nanoparticles only 35 and 32% BG and BB were degraded upon visible irradiation for 120 min. The recyclable of the Mg (0.050 M)-doped PbMoO₄ was verified under optimized environments. The outcomes establish that Mg (0.050 M)-doped PbMoO₄ nanoparticles exhibit substantially good stability with above 90 and 89% degradation after the sixth catalytic cycle. The scavenging (free radicals) tests revealed that ^•OH, h⁺, and ^•O₂⁻ radicals play main roles in BG and BB degradation. COD studies affirmed the whole mineralization of BG and BB dye molecules. The results reveal Mg-doped PbMoO₄ nanoparticles can be the superior candidates with strong catalyst stability for the removal of BG and BB in wastewater.