Understanding the interaction between active sites and sorbents during the integrated carbon capture and utilization process.

The distance between catalytic sites (Ni) and sorbents (CaO) on the performance of integrated CO 2 capture and utilization (ICCU) process is crucial important because the sorbents demonstrate a dramatic volume increase during carbonation reaction (1st stage of ICCU) and sequentially cover the catalytic sites and retard the CO 2 conversion (2nd stage of ICCU). Herein, we synthesized various Ni/CaO-based dual functional materials (DFMs) with different distances between active sites and sorbents to provide different volume spaces for the growth of CaCO 3 during the carbonation reaction. It is found that both 1%NiCaO and 10%NiCaO synthesized by a one-pot method exhibited a low CO 2 conversion (38% and 45%, respectively) and CH 4 selectivity (58% and 69%, respectively) as the distance between catalytic sites and sorbents was so close that the Ni active sites were covered by the formed CaCO 3 during carbonation reaction. With the increase of the distance by physical mixing method, the CO 2 conversion and CH 4 selectivity of 1%Ni/CeO 2 -CaO-phy were largely increased to 62% and 84%, respectively at 550 °C and atmospheric pressure when captured CO 2 from 15% CO 2 /N 2. This is attributed to the fact that the Ni active sites were still well dispersed on the surface of CeO 2 nanorods instead of being covered by the newly formed CaCO 3. [ABSTRACT FROM AUTHOR]