Morphology-tailored synthesis and electrochemical performances of CuBi₂O₄ hierarchical architectures with the aid of KCl

Abstract

The effect of the structure-directing agent KCl on the synthesis of CuBi₂O₄ hierarchical architectures was investigated. It is demonstrated that KCl plays an important role in tailoring the morphology of the products. By varying the KCl concentration from 0, 0.0625, 0.125, 0.25, 0.5, to 1.5 M, it brings about the synthesis of cauliflower-like agglomerate assembled by nanoparticles, cauliflower-like microsphere assembled by nanorods, dumbbell-like architecture constructed from nanorods, flower-like cluster formed from irregular nanoflakes, cuboid-like architecture made up of nanoparticles, and dumbbell-like architecture built from rectangular nanorods, respectively. Ultraviolet-visible diffuse reflectance spectroscopy reveals that the as-prepared samples have similar bandgap energy of 1.89 eV. The electrochemical performance of the samples was investigated by cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy in 2 M KOH electrolyte. Among the samples, the cauliflower-like agglomerate prepared at n(KCl) = 0 M delivers a relatively higher specific capacitance, reaching 1256 F g⁻¹ at the current density of 2 A g⁻¹.

Keywords:

• CuBi₂O₄
• self-assembled hierarchical architecture
• KCl structure-directing agent
• morphological tailoring
• electrochemical performance