“…In the last five years, Fe-based materials are mainly prepared by the simple pyrolysis of transition metal salt (FeCl3 [34,36,39,41,47,[73][74][75][76][77][78][79][80], Fe(NO3)3 [81][82][83][84], FeAc [24,74,[85][86][87][88], and FeC2O4 [42]), carbon support, and nitrogen-rich small molecule [34,36,78,79,85,[87][88][89] or polymeric compound [7,[39][40][41]90]. An important breakthrough was made by Zelenay et al [7] who successfully synthesized Fe/N/C catalysts (PANI-Fe-C) via heat-treatment of polyaniline (PANI), FeCl3 and carbon black (Ketjenblack EC-300J).…”