Self-assembled BiFeO3@MIL-101 nanocomposite for antimicrobial applications under natural sunlight

Abstract

In this paper, we report on the synthesis of a new hybrid photocatalytic material activated by natural sunlight irradiation. The material consists of multiferroic nanoparticles of bismuth ferrite (BFO) modified through the growth of the Fe-based MIL-101 framework. Material characterization, conducted using various techniques (X-ray diffraction, transmission electron microscopy, FTIR, and X-ray photoelectron spectroscopies), confirmed the growth of the MIL-101 metal-organic framework on the BFO surface. The obtained system possesses the intrinsic photo-degradative properties of BFO nanoparticles significantly enhanced by the presence of MIL-101. The photocatalytic activity of this material was tested in antibacterial experiments conducted under natural sunlight exposure within the nanocomposite concentration range of 100-0.20 µg/ml. The MIL-modified BFO showed a significant decrease in both Minimum Inhibiting Concentration and Minimum Bactericide Concentration values compared to bare nanoparticles. This confirms the photo-activating effect of the MIL-101 modification. In particular, they show an increased antimicrobial activity against the tested Gram-positive species and the ability to begin to inhibit the growth of the four Escherichia coli strains, although at the maximum concentration tested. These results suggest that the new nanocomposite BiFeO₃@MOF has been successfully developed and has proven to be an effective antibacterial agent against a wide range of microorganisms and a potential candidate in disinfection processes.

Keywords: E. coli; Ferrites; Hybrid material; MOF; Photo-activity.

Fig. 1

Schematic representation for the synthesis of hybrid nanomaterial BFO@MIL-101

Fig. 2

X-ray patterns of bare bismuth ferrite powder (black line), simulated MIL-101(Cr) (red line) and BFO@MIL-101 (blue line)

Fig. 3

SEM morphology of a bare bismuth ferrite and b BFO@MIL-101

Fig. 4

XPS spectra of Bi 4f (a, e), Fe 2p (b, f), N 1s (c, g) and Cl 2p (d, h), of MNPs@MIL (a–d) and bare MNPs (e–h)

Fig. 5

XPS spectra of C 1s (a, c) and O 1s (b, d) of bare MNPs (a, b) and MNPs@MIL-101 (c, d)

Fig. 6

FTIR spectra of bismuth ferrite nanoparticles (black line), hybrid BFO@MIL-101 after 2 h (red line) and hybrid BFO@MIL-101 after 4 h (blue line)

Fig. 7

TEM images of a bare bismuth ferrite, b hybrid BFO@MIL-101 after 2 h and c hybrid BFO@MIL-101 after 4 h