Integrated CO2 capture and conversion performance of Ni-CaO dual functional materials pellets in O2-containing flue gas stream

Efficient Ni-CaO dual function materials (DFMs) pellets show potential in integrated CO2 capture with reversed water gas shift reaction (ICCU-RWGS) for syngas production. However, the presence of O2 in industrial flue gas might affect their ICCU-RWGS performance. In this work, Ni-CaO DFMs pellets were synthesized via the extrusion-spherization method, and the ICCU-RWGS performance of the pellets in O2-containing stream was investigated. The surface basicity of the pellets decreased, and CO2 capture capacity decreased from 10.32 to 8.40 and 6.53 mmol CO2/g when the pellets were exposed to 2 % O2 and 15 % O2, respectively. The presence of 2 %O2 in flue gas resulted in the decay in catalytic activity, and CO yield declined from 6.0 to 5.08 mmol CO/g. Interestingly, the oxidative deactivation of Ni in O2 and the decrease of catalytic activity had avoided the unexpected release of CO in the CO2 capture stage, making the CO2 separation process more efficient.