Investigation of T site variation in spinel aluminates TAl2O4 (T= Mg, Zn & Cu), and formation of electrocatalyst CuAl2O4/carbon for efficient sensing application

Spinel structured aluminates TAl₂O₄ (T = Mg, Zn, and Cu) were synthesized by a facile hydrothermal method. The resultant enhancement in the electrochemical behavior was achieved due to the covalent synergism among the elements coexisting together. Structural and morphological characterizations were performed by X-ray diffraction, Fourier transform infrared spectroscopy, Raman spectroscopy, and field emission scanning electron microscopy. MgAl₂O₄, ZnAl₂O₄ and CuAl₂O₄ has displayed same space group Fd3m of Laue class lattice type of the cubic structure as they were synthesized at same temperature (600 °C). CuAl₂O₄ spinel structure displayed a nanoneedle like structure along with the small sized cylindrical particles alongside to which CuAl₂O₄ spinel is combined with activated carbon (CuAl/C) and was applied to develop a facile sensor for the electrochemical detection of Acetaminophen (ACAP) using cyclic voltammetry (CV) and differential pulse voltammetry (DPV), which exhibited maximum conductivity, and a substantial electroactive surface area. Finally, the defect-rich composite, CuAl/C, showed excellent sensor performance towards DPV with 21.5 nM limit of detection (LOD) in a wide linear working range of 0.199 μM–165.88 μM ACAP concentration, with a high sensitivity of 19.1221 μA μM⁻¹cm². Additionally, the sensor showed excellent recovery results in real-time analysis for environmental aquatic samples like industrial wastewater and Tuna Fish.