the prepared heterogeneous catalysts (NZVI/NaY and unsupported NZVI) exhibited excellent catalytic activities without
external energy input (i.e., without addition of ultraviolet light, ultrasound and electrical energy, etc.).
This result also indicated that the high surface energy made nano-Fe0 reactive and easy to get oxidized. The produced Fe2+ was further oxidized to Fe3+ in the Fenton process, and then the Fe3+ could be reduced to Fe2+ rapidly by the assistance of Fe0.