Effective dual role catalyst of mixed oxide heterostructure for photocatalyst and electrocatalytic sensing of isoniazid

The hetero-composite metal oxide nanostructures have received great attention owing to their synergistic microstructural features with distinct functionalities. Herein, CuO–Ce₂O₃ mixed metal oxide (MMO) was synthesized using facile and effective hydrothermal approach. The catalyst material was characterized with essential analytical techniques to confirm the phase, crystallinity and surface morphology. As an active catalyst, the dual performances of effective photodegradation of methylene blue (MB) and electro-oxidative sensing of Isoniazid (INH) was observed. The photodegradation of MB was investigated in the presence of O₂ ^·−, OH^· radicals and photogenerated holes (h⁺); among these three, h⁺ involved efficiently for MB photodegradation under visible light. From the Tauc plot, the bandgap energy for CuO and Ce₂O₃ were found to ~1.8 and ~2.7 eV respectively. Cyclic voltammetry was used to investigate the electro-oxidation of Isoniazid on CuO–Ce₂O₃ modified/glassy carbon electrode (GCE). It reveals that MMO can facilitate the electrochemical oxidation of Isoniazid with a great decrease in over potential from 0.8 to 0.4 V at pH 7 phosphate buffer solution. Furthermore, the MMO exhibits excellent catalytic performance towards electro-oxidation of INH over the linear range of 6–50 µM with low detection limit of 0.33 µM at 50 mV scan rate. Thus it can be concluded that MMO/GCE could be a potential bi-functional catalyst for the MB photodegradation and efficient sensing of INH.