NOVELTY - Preparing supported electrocatalyst, comprises: treating sample of multiwalled carbon nanotubes with aqueous hydrochloric acid solution; treating the multiwalled carbon nanotubes with a solution comprising e.g. nitric acid; mixing the resultant oxidized multiwalled carbon nanotubes with a mixture comprising polyaniline and iron species; vacuum-drying the mixture; subjecting vacuum-dried mixture to ball-milling; heating ball-milled mixture at first temperature, and cooling; treating the cooled, ball milled mixture with aqueous sulfuric acid; and heat-treating the mixture at second temperature.    USE - The process is useful for preparing the supported electrocatalyst (claimed), for a cathode for the oxygen reduction reaction in polymer electrolyte fuel cell.    ADVANTAGE - The process: utilizes the multiwalled carbon nanotubes, which has higher Brunauer-Emmett-Teller surface area of 230 meter2/gram, thus enabling to accommodate the highest density of active sites with more stability; and provides the non-precious supported electrocatalyst, which: exhibits improved catalytic activity, durability, mass transfer, water removal from catalyst surface, improved corrosion resistance and electron conductivity, when compared with traditional carbon black supported catalysts; and facilitates the complete reduction of oxygen to water.    DETAILED DESCRIPTION - Preparing a supported electrocatalyst, comprises: treating a sample of multiwalled carbon nanotubes with an aqueous hydrochloric acid solution to remove impurities from the carbon nanotubes; treating the multiwalled carbon nanotubes with a solution comprising nitric acid and sulfuric acid to provide oxidized multiwalled carbon nanotubes; mixing the oxidized multiwalled carbon nanotubes with a mixture comprising polyaniline and a iron species; vacuum-drying the mixture comprising the multiwalled carbon nanotubes, polyaniline and the iron species to form a vacuum-dried mixture; subjecting the vacuum-dried mixture to ball-milling for 24 hours; heating the ball-milled mixture at a first temperature in an inert atmosphere; cooling the ball milled mixture; treating the cooled, ball milled mixture with aqueous sulfuric acid; and heat-treating the mixture at a second temperature in the inert atmosphere. An INDEPENDENT CLAIM is also included for the supported electrocatalyst prepared by the process.