Enhancement in photocatalytic and electrochemical performance of hydrothermally synthesized β-Bi2O3 via Ni incorporation

Abstract

β-Bi2O3 and Ni-incorporated β-Bi2O3 nanoparticles with different Ni incorporating amounts (0, 2, and 4 at. wt. %) were successfully synthesized through a viable hydrothermal process. As-synthesized nanoparticles were analyzed by complementary analytical tools such as X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDS), UV–visible spectroscopy (UV–Vis), and photoluminescence spectroscopy (PL) for structural, microstructural, compositional, and spectral properties. The photocatalytic performance of synthesized nanoparticles was assessed by subjecting them to visible light irradiation and monitoring the decomposition of rhodamine-B dye. The findings demonstrated that the inclusion of Ni(4%) in β-Bi2O3 nanoparticles significantly enhanced its photocatalytic activity compared to pristine β-Bi2O3 which is desirable for environmental remediation. This improvement may be caused by increased generation of electron-hole (e−-h+) pairs, reduced recombination rate of these pairs, enhanced absorption of visible light, and a decreased band gap energy. To evaluate the specific capacitance characteristics of synthesized electrode materials, cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance analyses were conducted. The super capacitance activities of prepared electrode materials were observed in the order of Bi2O3 < Ni(2%)-Bi2O3 < Ni(4%)-Bi2O3. Notably, Ni(4%)-Bi2O3 nanocomposite exhibited higher supercapacitance, which can be attributed to the effective role of appropriate nickel incorporation in Bi2O3. These results suggested that the incorporation of Ni(4%) into β-Bi2O3 to form a nanocomposite showed greater capability as an effective electrode material for advanced energy storage devices, especially supercapacitors.