Enhanced Creatinine Adsorption Kinetics on Defective Polyhedral Morphology of Cu 2 O‐CuO@Pt ( 3d‐2p‐5d ) Nanohybrids for Electrochemical Sensing Application and DFT Investigation

ABSTRACT In this study, the defective polyhedral Cu 2 O‐CuO@Pt‐X (where X represents different Pt loading concentrations ranging from 0.005 to 0.25 m or 2–10 mg) was synthesized through a hydrothermal method combined with ultrasonic techniques. The concrete evidence from EPR, XPS, and HR‐TEM confirms that the Cu 2 O‐CuO@Pt‐X polyhedral structure exhibits remarkable defective sites (OV s and screw dislocation), heterointerfaces, and Pt cluster formation compared to different Pt dopings. Furthermore, the modified electrode surface achieves a broad linear range of 0.01–500 µ m and a detection limit as low as 0.0015 µ m in 0.05 m PBS for the detection of creatinine (Crt). Based on the DFT study, the adsorption energies of Crt‐NH 2 (∼ −1.3551 eV), Crt‐NHOH (∼ −1.896 eV), and Crt‐NO (∼ −1.2041 eV) were calculated at the different metal cation sites on the Cu 2 O‐CuO@Pt surfaces. The CV and DPV measurements also reveal that the oxime group (─NHOH) exhibits significantly higher adsorption energy, as evidenced by its lower onset potential and earlier oxidation behavior. Besides, the d‐band center (Ɛ d ) can be calculated by the PDOS data, such as Cu 2 O‐CuO@Pt (−0.5316 eV), Cu 2 O‐CuO (−2.6095 eV), Cu 2 O (−1.7189 eV), CuO (−2.4178 eV), and Pt (−0.3599 eV), respectively. These findings suggest that the higher attraction of Cu 2 O‐CuO@Pt for Crt‐NH 2 adsorption at the electrode interface is made due to its reduced d‐band center energy, robust orbital hybridization, and increased electron cloud density. Ultimately, this work schematically illustrates the generation of OV s within the crystal lattice, the heterointerface between Cu 2 O and CuO, and the labile electron transfer mechanism in the defective polyhedral Cu 2 O‐CuO@Pt‐X.