Facile fabrication of aluminum-oxide deposited CuO/CaO composites with enhanced stability and CO2 capture capacity for combined Ca/Cu looping process

The combined Ca-Cu looping process is a promising CO2 capture technology, in which the exothermic reduction of CuO with methane is used in situ to provide the heat required to calcine CaCO3. However, the CO2 capture capacity of CaO/CuO composites decreases rapidly during multiple cycles. Herein, we proposed an aluminum-oxide deposited CaO/CuO composites synthesized by the space-confined chemical vapor deposition method and systematically investigated in accordance carbonation, calcination-reduction, and oxidation cycles. The deposited CaO/CuO composites feature highly porous structures and fine grain sizes, demonstrating significantly enhanced CO2 capture performance with only 5 mol.% of Al stabilizer. The CO2 absorption amount of Cu1CaAl0.05 is 0.2183 g(CO2)/g(material) in the first cycle. After 20 cycles, it still maintains 86.6% of the original absorption capacity, exceeding that of the undeposited CaO/CuO composites by 115%. Moreover, during the 20 cycles, the oxidation conversion of Cu(1)CaAl(0.05 )always keeps above 95%, much higher than undeposited CaO/CuO composites. Various evidences indicate that the uniform deposition of aluminum-oxide on the CaO/CuO sorbent plays a vital role in improving the CO2 absorption performance and cycling stability.

Automated summary

In this study, aluminum-oxide deposited CaO/CuO composites with highly porous structures and fine grain sizes were synthesized using the space-confined chemical vapor deposition method. These composites exhibited significantly enhanced CO2 capture performance and cycling stability.