Synthesis of Al/starch co-doped in CaO nanoparticles for enhanced catalytic and antimicrobial activities: experimental and DFT approaches

Abstract

In this work, aluminum/starch (St)-doped CaO nanoparticles (NPs) were synthesized by a co-precipitation method to degrade harmful dyes in various pH media. Systematic characterization was performed to investigate the influence of Al/St dopants on the composition, crystal structure, functional groups present, optical characteristics, and morphology of CaO NPs. Further hybrid density functional analyses corroborated that the band gap energy was reduced as the Al concentration in starch-doped CaO is increased. Optical absorption spectra of the synthesized materials revealed a redshift upon doping, which indicated depletion in the band gap energy of Al/St-doped CaO. PL spectroscopy showed that the intensity of CaO was reduced by the incorporation of Al and St assigned to minimum electron-hole pair recombination. Interlayer spacing and morphological features were determined by HR-TEM. HRTEM revealed that the control sample has cubic NPs and the incorporation of St showed overlapping around agglomerated NPs. The d-spacing of CaO was little enhanced by the inclusion of dopants. Experimental outcomes indicated that the addition of Co-dopants improved the catalytic potential of CaO NPs. Al (4%)/St-doped CaO NPs expressed a significant reduction of methylene blue in a basic environment. The maximum bactericidal performance was observed as 10.25 mm and 4.95 mm in the inhibition zone against S. aureus and E. coli, respectively, after the addition of Al and St in CaO.