Fig. 4

FTIR spectra of the IONPs synthesized in green via magnetotactic bacteria and silver-doped IONPs: (a) bacterial extract, (b) Fe2O3 NPs, (c) Fe3O4 NPs, (d) bacterial extract with a wavenumber range of 400–1000 cm−1, (e) Fe2O3 NPs with a wavenumber range of 400–1000 cm−1, (f) Fe3O4 NPs with a wavenumber range of 400–1000 cm−1, (g) Ag-doped Fe3O4 NPs, and (h) Ag-doped Fe2O3 NPs.