Efficient photocatalytic degradation of diclofenac drug using the ZnPrAlO photocatalyst under UV light irradiation.

Herein, we report the efficient photocatalytic degradation of the diclofenac drug using the ZnPrAlO photocatalyst [x, y] = (0.00, 0.00), (0.03, 0.01), (0.03,0.03) under UV light irradiation. The analysis of the structure reveals that the Pr and Al cations insertion into the ZnO lattice leads to a decrease in the lattice constant (a and c), Zn-O bond length, strain lattice, and crystallite size. These alterations are linked to the high degree of atomic disorder triggered by the dopants, which produce stress and strain in the ZnO structure. The Raman measurements confirmed the structural phase and showed changes in the position and intensity of the E mode, associated with oxygen vibrations and material crystallinity. The presence of the dopants reduces the concentration of V and V type defects while increasing the levels of V, V, and O defects, as observed from the fitting of the Photoluminescence spectra. Furthermore, it was noted that de Pr and Al cations insertion into ZnO increases the optical band gap, which is associated with the Moss-Burstein effect. The micrograph images show that dopants transform the morphology from quasi-spherical particles to irregular cluster structures. The textural analysis indicated that an increase in the concentration of Al in the ZnO lattice led to a higher surface area, likely enhancing photocatalytic activity. The sample containing 3% Pr and 3% Al showed the highest photocatalytic activity and degraded up to 71.42% of diclofenac. In addition, experiments with scavengers revealed that hydroxyl radicals are the main species involved in the drug's photodegradation mechanism. Finally, the ZnPrAlO compound is highly recyclable and stable.