Selective Reduction of Oxygen on Non-Noble Metal Copper Nanocatalysts

Efficient removal of molecular oxygen (O₂) from flue gas is necessary to capture and utilize carbon dioxide (CO₂) from fossil-fuel sources. Herein, the catalytic reduction of O₂ in simulated flue gases using alumina-supported copper (Cu) nanostructures is presented. The Cu catalyst outperformed conventional palladium systems for the selectivity toward CO₂ over carbon monoxide (CO). Varying the reactant feed ratio can lead to structural rearrangements at the surface of Cu nanoparticles, resulting in significant differences in catalytic activity. Under optimal conditions, a favorable Cu@CuO_x core-shell structure is observed to exhibit both excellent activity and selectivity to CO₂. The simulated flue gas is purified from 85% to >99.9% (v/v) CO₂ after passing the catalytic system. The catalyst also exhibits high stability, showing only ≈0.1% drop in CO₂ after 10 h on stream. This design marks progress toward the sequestration of CO₂ and the development of non-noble catalysts by tuning their dynamic nanostructures under controllable reaction conditions.