Sequestration or utilization of carbon dioxide (CO2) produced from fossil fuels depends on the ability to transform flue gas into purified streams. Recent developments in oxy‐combustion have improved the efficiency of energy generation and carbon capture (>90% CO2). The subsequent removal of oxygen (O2) from this flue gas is critical, but such a process is energy intensive, technologically challenging, and unsolved. Herein, a simulated flue gas stream is purified by the catalytic conversion of oxygen using methane (CH4). The supported palladium (Pd) catalyst selectively reduces oxygen to an effluent gas with 99.7% CO2 and 0.3% O2. Using a higher Pd loading has no impact on the oxygen conversion, whereas feeding excess CH4 decreases the selectivity to CO2. A complete removal of O2 is achieved using a copper‐based oxygen scavenger placed after the Pd catalyst bed, yielding a 100.0% pure CO2 stream.