Preparation and characterization of phase pure monoclinic α-Bi2O3 nanoparticles and influence of Ni2+and Cu2+ impregnation on their photocatalytic properties

Nowadays, pharmaceutical waste, Naproxen (NPX) as well as the dye fuchsin blue (FB) become hazardous pollutant due to their toxic behavior. Because of toxicity, the efficient removal of them from water has become one of the most vital challenge. Yet, due to high cost, low degradation efficiency, of the known catalyst restrict their real life applications. In this perspective, metal ions impregnated (Ni2+ and Cu2+) Bi2O3 heterostructures have been investigated as a potential material for photocatalytic degradation of NPX and FB. These materials are synthesized by simple wet-impregnation method and thoroughly characterized by various methods such as XRD, DLS, SEM, EDS, HRTEM, XPS, etc. The diffraction patterns confirm formation of phase pure alpha-Bi2O3 nanoparticles. The zeta potential (-25 mV) of Bi2O3 nanoparicles confirms presence of negatively charges oxide groups in its surface that can act as anchors for divalent anions. The impregnated hybrids shows considerably smaller zeta potential values (-15 and-17 mV for Ni2+-Bi2O3 and Cu2+-Bi2O3 respectively). The XPS studies reveal presence of surface bound divalent metal ions. The adsorption edge of Ni2+-Bi2O3 and Cu2+-Bi2O3 nanostructures were shifted slightly towards lower frequency. The photoluminescence spectrum impregnated materials shows significant quenching compare to pristine Bi2O3. suggesting lesser degree electron-hole recombination upon metal loading. Due to the photocatalytic degradation efficiencies of both Ni2+-Bi2O3 (87% for FB and 79% for NPX) and Cu2+-Bi2O3 (73% for FB and 70% for NPX) heterostructures are significantly higher compare to the pristine one (43% for FB and 40% for NPX). The photo degradation process obeys the pseudo first order kinetics. Due to simpler synthesis and enhanced activity metal ion loaded Bi2O3 photocatalysts can be potential photo-catalysts for removing NPX and FB from wastewater.

Automated summary

Metal ion impregnated Bi2O3 heterostructures show significantly higher photocatalytic degradation efficiencies for Naproxen and dye fuchsin blue, compared to pure Bi2O3, due to enhanced activity and simpler synthesis.