The redox reaction of the fuel cells first occurs as the fuel, hydrogen, is fed through the anode, where it undergoes an oxidation reaction that occurs with the hydrogen fuel (H 2 → 2H + + 2e -), the hydrogen atom is then separated into cations and electrons by the catalysts inside the anode. The cations will move from the anode to the cathode through the electrolyte. During this process, the proton will be surrounded by a proton-conducting polymer, facilitating H + transport across the electrolyte. The hydrogen ions (H + ) from the electrolyte will then be integrated into the reduction reaction to combine the electrons to form water. As water is released as a by-product of this reaction, electricity will be generated from the whole reaction . Simultaneously, the electrons from the anode will then flow through an external circuit from the anode to the cathode, producing direct current electricity. At the cathode, another catalyst causes oxygen to react with the cations and electrons flown from the anode to react in another redox reaction (O 2 + 4H + + 4e -→ 2H 2 O), forming water . This redox reaction, or else called the oxygen reduction reaction (ORR), is an essential process for energy conversion within fuel cells; molecular oxygen (O 2 ) is reduced to water due to higher current, thereby releasing energy that contributes to overall electricity generation while also generating the electrical potential that generates the electricity outputted within the fuel cell, making it the critical reaction in converting energy . Within this reaction, catalysts determine the efficiency of this reaction as it help break the bonds of the molecular oxygen (O 2 ). A better catalyst results in faster reactions, thereby improving the fuel cell's overall performance.