Sequential Oxygen Reduction and Adsorption for Carbon Dioxide Purification for Flue Gas Applications

Sequestration or utilization of carbon dioxide (CO ₂ ) 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% CO ₂ ). The subsequent removal of oxygen (O ₂ ) 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 (CH ₄ ). The supported palladium (Pd) catalyst selectively reduces oxygen to an effluent gas with 99.7% CO ₂ and 0.3% O ₂ . Using a higher Pd loading has no impact on the oxygen conversion, whereas feeding excess CH ₄ decreases the selectivity to CO ₂ . A complete removal of O ₂ is achieved using a copper-based oxygen scavenger placed after the Pd catalyst bed, yielding a 100.0% pure CO ₂ stream.