Investigations on the enhanced photocatalytic activity of (Ag, La) substituted nickel cobaltite spinels

Abstract

This work reports the synthesis of NiCo2O4 (NCO), Ni0.95Ag0.05Co2O4 (NACO), and Ni0.95Ag0.05Co1.95La0.05O4 (NACO) by a simple sol-gel route and the evaluation of their photocatalytic activity towards the organic dye Evans blue. The synthesized photocatalysts were characterized by analytical techniques such as XRD, FTIR, SEM, particle analyzer and UV–Vis spectroscopy. The XRD patterns proved that the prepared samples crystallized in the cubic spinel structure. The related structural parameters were also evaluated. The SEM micrographs revealed that all the samples possessed agglomerated uneven structure. The particle size was found to decrease with the addition of dopants. The photocatalytic efficiency was validated using UV–vis spectroscopy, which proved the relatively narrow bandgap of the spinels. The photocatalytic activity of the undoped and doped samples against the Evans blue dye under visible light irradiation has been systematically studied. The superior photocatalytic activity was witnessed for (Ag, La) co-doped NiCo2O4. Conclusively, a possible mechanism for the photo-degradation of the dye was established. Hence rare earth doped cobaltites serve as a potential candidate for resolving the crucial environmental pollution.