Both catalytic combustion (CC) and chemical looping combustion (CLC) are promising technologies for energy saving and emission reduction of CO2 in treatment of steelmaking off-gas (CO).
Recently, researchers from the Institute of Mechanics of the Chinese Academy of Sciences (IMCAS), Tianjin University of Science and Technology and Aalto University have provided new insights into the microscopic reaction mechanism of CO in CC and CLC processes over the cubic Cu2O catalyst.
Related results were published in Applied Catalysis B: Environmental.
The researchers compared the evolution behavior and quantitative reaction mechanisms of cube Cu2O model catalyst for CC and CLC reactions. They found that the Cu2O-CC exhibited higher activity and stability than Cu2O-CLC.
The typical characterization results suggested that the only surface unstable Cu2O was oxidized to CuO, showing excellent synergistic effect of metal-oxide interface between Cu+/Cu2+ and active lattice oxygen species for Cu2O-CC reaction. However, CLC reaction caused Cu2O structure collapse and then low stability and agglomeration of CuOx species.
The researchers proposed three different active oxygen species (surface cycle lattice oxygen, bulk lattice oxygen, and adsorbed oxygen) and detailed reaction pathways.
Results showed that the intrinsic activity of surface cycle lattice oxygen was higher in terms of turnover frequency and facile formation of C16O18O on the cubic interface of Cu2O-CC through adsorbed CO during CC process.
These findings can help us to better understand the actual surface reaction process on cubic Cu2O catalyst in the CC and CLC, and provide theoretical support to the advanced catalyst design and intrinsic mechanism research for CC and CLC processes.
