Mn, Mg-doped ZrO2 nanoparticles: a photostable catalyst for enhanced mineralization and photocatalytic degradation of MV and MB dyes under sunlight irradiation

In the study, pure ZrO 2 and co (Mn, Mg)-doped ZrO 2 samples were prepared by the Co-precipitation technique. The products were investigated by XRD, UV–DRS, PL, FT-IR, FESEM-EDS, and TEM techniques and confirm Mn and Mg doping in ZrO 2 crystal. Mn (0.05 M) and Mg (0.02–0.08 M) ions into ZrO 2 host lattice with altering crystal structure from tetragonal to monoclinic ZrO 2 phase were confirmed by XRD analysis. The energy gap of the doped products considerably narrows (3.2 eV–2.3 eV) towards the visible region, which was allocated to hybridizing of orbital of host, dopant and surface defects or impurities that triggered sunlight photodegradation activity. FESEM and TEM analysis depicts quasi-spherical morphology with slight agglomeration for obtained Mn (0.05 M), Mg (0.04 M)-doped ZrO 2 nanoparticles. The ZrO 2 and co (Mn, Mg)-doped ZrO 2 samples were employed for photodegradation of both (MV and MB) dyes in eco-friendly sunlight irradiation. Amongst all products, Mn (0.05 M) and Mg (0.04 M) concentrations in ZrO 2 demonstrated much higher photodegradation efficiency (95 and 97%) as compared with pure ZrO 2 (33 and 34%), Mn (0.05 M), Mg (0.02 M) doped ZrO 2 (68 and 69%), Mn (0.05 M), Mg (0.06 M) doped ZrO 2 (77 and 79%) and Mn (0.05 M), Mg (0.08 M) doped ZrO 2 (86 and 88%) in 70 min of irradiation. The photodegradation was further confirmed by COD and scavenger analysis. The reusability study established stability and effectualness of Mn (0.05 M) and Mg (0.04 M) doped ZrO 2 nanoparticles for six cycle runs.