Although an increasing interest has been attracted to further develop heterostructured catalysts from metallic glasses(MGs)by heat treatment,overcoming surface oxidation effect is still a critical problem for such environmental catalysts.Herein,a short-time electrochemical etching of partially crystallized Fe-based ribbons in 0.3 M H3PO4 electrolyte enables the formation of honeycomb-like nanoporous structure as effective catalytic active sites in Fenton-like process.Studies of structure and surface morphologies reveal that the formation of nanoporous structure by potentiostatic etching originates from electrochem-ical potential difference of nanocrystals(α-Fe(Si)and Fe2B)and residual amorphous phase in partially crystallized ribbons,where Fe2B having a lower open circuit potential tends to be selectively dissolved.Simultaneously,thin oxide layer after electrochemical etching exposes more active sites for H2O2 activa-tion and provides an effective protection of nanocrystals from massive loss during etching.Investigation of optimal processing conditions suggests that the selection of electrolyte plays an important role;dye degradation rates of etched ribbons in HNO3 and Na2SC4 electrolytes can also achieve at least 2 times higher than that of as-annealed ribbons.This work holds the promise to develop novel environmental catalysts by effective electrochemical etching of partially crystallized ribbons.