Ternary Ceo2-Cuo@Graphene Oxide Nanocomposites for Sensing L-Tyrosine: Experimental and Density Functional Theory Studies

Abstract

Recent advancements in the design of ternary nanocomposites combining various metal oxide nanoparticles and carbon-based materials have garnered attention. In this study, the novel trinary CeO2-CuO@rGO nanocomposites were synthesized to investigate the synergistic effect for sensing L-tyrosine in comparison with the binary nanocomposites, as well as copper oxide and cerium oxide nanoparticles. X-ray powder diffraction, Fourier-transform infrared spectroscopy, and field-emission scanning electron microscopy coupling with energy dispersive spectroscopy and elemental mapping were employed to examine the structure, morphology, and composition of these nanocomposites. Electrochemical results revealed that the ternary nanocomposite showed superior performance, detecting L-tyrosine at a limit of detection of 35 nM with two distinct linear ranges of 10-7 to 1.31 × 10-3 M and 1.3 × 10-3 to 5.0 × 10-3 M. Quantum mechanical modeling was also conducted to understand the adsorption configurations and interaction energies of L-tyrosine on the surfaces of copper oxide, cerium oxide, and graphene oxide substrates. DFT-D3 calculations show that the most stable equilibrium adsorption geometries of L-tyrosine molecule on GO(001) pristine bonded through the opening of the epoxy ring, while the placement of L-tyrosine molecule on both Cu2O(111) and CeO2(111) surfaces via the double bond of HN−Cu and COO-Cu showed the lowest interaction energies. In addition to O−H⋯N hydrogen bond, O⋯H−N hydrogen bond and to some extent O⋯H−O hydrogen bond play an important role in the internal stability of the adsorbed L-tyrosine molecule on the substrates. These results provide insights into the structural and functional advantages of ternary nanocomposites for enhanced sensing applications.

Keywords: L-Tyrosine, Ternary Nanocomposite, CeO2-CuO@rGO, DFT-D3