One of the major challenges associated with fuel cells is the design of highly efficient electrocatalysts to reduce the high overpotential of the oxygen reduction reaction (ORR).Here we report Polyaniline (PANI) based micro/nanomaterials with or without transition metals,prepared by the emulsion polymerization and subsequent heat treatment.PANI microspheres with the diameter of about 0.7am have been prepared in basic (NH3 solution) condition,using two different types of surfactant (CRAB,SDS) as the stabilizer,ammonium persulphate (APS) as oxidant with aniline/surfactants molar ratio at 1/1 under the hydrothermal treatment.PANI nanorods,Fe-PANI,and Fe-Co-PANI have been synthesized in acidic (HCI) medium with aniline/surfactants molar ratio at 1/2 and polymerization carried out without stirring for 24 h.Products mainly Fe-Co-PANI have shown high current density with increasing sweep rate and excellent specific capacitance 1753 F/g at the scan rate of 1 mV/s.Additionally,it has shown high thermal stability by thermogravimetric analysis (TGA).Fe-PANI has been investigated for excellent performance toward ORR with four electron selectivity in the basic electrolyte.The PANI-based catalysts from emulsion polymerization demonstrate that the method is valuable for making non-precious metal heterogeneous electrocatalysts for ORR or energy storage and conversion technology.