Fig. 1.

Fe-based perovskite TMOs as peroxidase mimics. a Schematic of ABO₃ perovskite structure. A (rare earth or alkaline-earth metal), B (transition metal), and O are shown in gray, blue, and yellow, respectively. b 3d electron occupancy of t_2g (π*) and e_g (σ*) antibonding orbitals associated with the transition metal, for LaFeO₃, La_0.5Sr_0.5FeO_3-δ, and SrFeO_3-δ. c TEM image of LaFeO₃. Scale bar: 200 nm. d PXRD patterns of LaFeO₃, La_0.5Sr_0.5FeO_3-δ, and SrFeO_3-δ (the red lines at the bottom mark the reference pattern of LaFeO₃ from the JCPDS database, card number 75-0541). e Typical absorption spectra of 0.8 mM TMB after catalytic oxidation with 50 mM H₂O₂ in pH 4.5 acetate buffer at 40 °C, in the presence of 10 μg mL⁻¹ of LaFeO₃, La_0.5Sr_0.5FeO_3-δ, and SrFeO_3-δ nanozymes. f Time evolution of absorbance at 652 nm (A₆₅₂) for monitoring the catalytic oxidation of 1 mM TMB with 100 mM H₂O₂ in the presence of 10 μg mL⁻¹ of LaFeO₃, La_0.5Sr_0.5FeO_3-δ, and SrFeO_3-δ nanozymes. g Specific peroxidase-like activities of LaFeO₃, La_0.5Sr_0.5FeO_3-δ, and SrFeO_3-δ. h Specific peroxidase-like activity of the Fe-based perovskite TMOs as a function of e_g occupancy. Source data are provided as a Source Data file