Fig. 1

Characterizations of the FMDHN. A SEM images of FMHN and B FMDHN. C TEM images of FMDHN. D the size distribution and E N2 adsorption–desorption isotherms [F The size of pores on FMHN is indicated by the inset] of FMHN. G Zeta potential values of Fe3O4 nanozymes and FMHN. H XRD patterns of the synthesized Fe3O4 nanozymes and FMHN