Barium oxide nanorods: Catalyst concentration and surface defects' role in degrading methylene blue organic pollutant

Abstract

In this study, BaO nanorods (NRs) were synthesized with inherent surface defects using the chemical coprecipitation process. The rich oxygen defect BaO NRs exhibited enhanced light sensitivity and effectively interacted with the organic pollutant methylene blue (MB) dye under UV-light illumination for wastewater treatment. The X-ray diffraction (XRD) analysis confirmed the highly crystalline tetragonal structure of the BaO NRs. Microstructural characteristics were examined using theoretical approaches such as Debye-Scherrer (DS), Williamson-Hall (W-H), and Size-Strain Plot (SSP), revealing an average crystallite size of approximately 30 nm. Field emission scanning electron microscopy (FE-SEM) revealed the rod-shaped structure of the BaO nanorods, with particles aligned on top of each other. UV–visible absorption studies demonstrated an increased optical bandgap in the BaO NRs compared to the bulk material. Photoluminescence spectroscopy revealed the presence of oxygen traps and surface defects, which aided the photodegradation process. The photocatalytic activity of the BaO NRs was assessed by degrading MB dye. We found that a concentration of 150 mg of BaO NRs exhibited the highest degradation efficiency at 85 %.