Hierarchical self-assembly of 0D/2D β-Bi2O3 crossandra flower morphology exhibits excellent photocatalytic activity against bromophenol dyes

Abstract

Crossandra flower shape morphology of β-Bi2O3 nanoflakes was achieved successfully by the solvothermal method. Synthesized β-Bi2O3 nanoflakes were characterized using various characterization techniques such as Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Raman spectra, Ultraviolet–Visible diffuse reflectance spectroscopy (UV-DRS), X-ray photoelectron spectrometer (XPS), N2 adsorption-desorption isotherms (BET), liquid chromatography with mass spectrometry LCMS, Dynamic light scattering (DLS) and Zeta potential (ZP). Moreover, thermal stability and phase change were studied using thermogravimetric analyzer (TGA) and differential thermal analyzer (DTA). The size, shape, and extent of growth was studied using transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDAX), and field emission scanning electron microscopy (FESEM). The crossandra flower shape morphology was achieved due to the effect of temperature (350 °C); this was due to the uniform shifting of heat throughout the material during calcination, which allows material growth along the c-axis. The obtained material was partially in de-agglomerated and agglomerated form, and agglomeration was due to electrostatic forces of attraction. Besides this, the synthesized β-Bi2O3 was utilized to investigate photocatalytic activity for the degradation of bromophenol blue (BPB) and bromocresol purple (BCP). β-Bi2O3 shows the effective catalytic activity as it degrades the phenolic dyes effectively. The degradation was 96% (160 min) and 94% (200 min) for BPB and BCP, respectively. Overall, β-Bi2O3 nanoflakes were more responsive as a photocatalyst for BPB, which took minimal time as compared to BCP.