Urbach energy and band gap engineering of spinel cobalt manganese oxide for enhanced photocatalytic removal of organic pollutants

CoMn2O4 is a mixed transition metal oxide that belongs to the spinel family. Despite its unique properties, it suffers from limitations due to its wide band gap, high recombination rate, and limited charge mobility. This study provides strategies to overcome such limitations. The first strategy adopted to tune the band gap of the metal oxide is vanadium doping. Secondly, vanadium-doped cobalt manganese oxide was combined with graphitic carbon nitride (gCN) to prepare a composite. The synergistic effect of these two approaches led to improved photocatalytic activity, driven by suppressed e-/h+ pair recombination and increased surface area provided by gCN. V-CoMn2O4@gCN removed 94.37 % rhodamine B as compared to the pure and doped catalysts. Similar results were observed for ciprofloxacin: the prepared composite removed 90.07 % of the drug, The prepared composite showed the highest percentage removal for both organic pollutants; hence, the results obtained from the photocatalytic experiment are consistent with the expected outcomes.