In the context of fuel cell technology, the selective oxidation of CO in hydrogen-rich mixtures is a crucial process. In order to effectively remove the hydrogen-rich stream from CO, the reactions have been carried out in an excess oxygen gas at a temperature range of 150-200°C. Over rare earth enhanced nickel catalysts, selective oxidation of natural gas to produce syngas was studied. It was discovered that rare earth oxides, such as Y2O3 and CeO2, were effective promoters of higher product yields and selectivity. A chemical process known as hydrogenation occurs when molecular hydrogen (H2) reacts with another substance or element, often in the presence of a catalyst made of nickel, palladium, or platinum. It is frequently used to decrease or saturate organic molecules.