CeO ₂ /Polyaniline Nanocomposite with a Wasp Nest-like Morphology for Supercapacitor and Sensing Applications

Encapsulation increases the versatility of materials for synthetic purposes by changing their properties. In this study, the PANI-encapsulated CeO2 nanocomposite was prepared through hydrothermal treatment, followed by the oxidative polymerization method, which yields the CeO2 eggs in a PANI wasp nest structure-like morphology. The unique structure of the CeO2/PANI nanocomposite was used for supercapacitor and sensor applications. Under optimal conditions, the CeO2/PANI nanocomposite delivers a specific capacitance of 487.5 F g–1 at a current density of 1 A g–1 with a 79% rate capability at 20 A g–1. The activated carbon//PANI/CeO2 device delivers a cell-specific capacitance of 242.7 F g–1 at a current density of 1 A g–1. It provides energy and power densities of 109.25 Wh kg–1 and 9000 W kg–1, respectively, with 95.7% cyclic stability after 9000 GCD cycles at 10 A g–1. Furthermore, the fabricated GC-CeO2/PANI electrode surpasses previous electrodes for tryptophan oxidation by reducing the oxidation potential to 0.67 V, offering a wide linear range from 4.5 to 160 μM and providing a low detection limit of 1.56 μM. Apart from high sensitivity, the GC-CeO2/PANI electrode also exhibited selectivity and long-term stability for tryptophan detection. The remarkable performance of the CeO2/PANI nanocomposite highlights its potential for supercapacitor and sensor applications while also paving the way for advancements in multifunctional energy applications.