High Electrochemical Performance and Enhanced Electrocatalytic Behavior of a Hydrothermally Synthesized Highly Crystalline Heterostructure CeO@NiO Nanocomposite.

A CeO-based heterostructure nanocomposite has been attractive as an electrode material for energy storage and as an electrochemical sensor. In the present work, a CeO@NiO nanocomposite was prepared by a simple hydrothermal method. The structural and morphological information on the heterostructure CeO@NiO nanocomposite were obtained by using different characterization methods like X-ray diffraction, UV-visible, Fourier transform infrared, electron paramagnetic resonance, Raman, field-emission scanning electron microscopy, high-resolution transmission electron microscopy, energy-dispersive X-ray elemental color mapping, X-ray photoelectron spectroscopy, and thermogravimetric analysis. Compared with pristine CeO, the heterostructure CeO@NiO nanocomposite exhibits a higher electrochemical performance with a specific capacitance of 317 F g at a current density of 1 A g in a 1 M KOH electrolyte. This device demonstrates a high energy density and a power density of 11 Wh kg and 750 W kg, respectively. Besides, it was found that CeO@NiO/glassy carbon electrode (GCE) shows appreciable electrocatalytic activity toward NO oxidation. The CeO@NiO-modified electrode displays a linear response for NO oxidation between 0.001 × 10 and 4 × 10 M. Apart from high sensitivity (2260 μA mM cm), the CeO@NiO-modified electrode also exhibits good selectivity and long-term stability for nitrite (NO) detection in a water real sample, and the obtained results showed excellent recovery. The encouraging electrochemical performance of the CeO@NiO nanocomposite provides a promising approach for the development of multifunctional electrode materials for future energy storage devices and sensors.