CaO-based CO2 sorbents play a significant role in sorption enhanced methane steam reforming process for hydrogen production and CO2 emission reduction. However, the sorbents suffer from decreasing CO2 sorption capacity and stability due to the sintering of CaO grains. In this work, we modified CaO sorbents by incorporating Ce to obtain CeO2/CaO sorbents via a modified sol-gel method. CO2 sorption evaluation shows that the relative molar ratio of CaO to CeO2 plays an overwhelming role in the CO2 sorption capacity and stability of the CeO2/CaO sorbents. Superior CO2 sorption ratio (83.65% for sorbent with Ca/Ce molar ratio of 15) was achieved, after 25 cycles, which was 1.49 times higher than that of the as-synthesized pure CaO sorbent. The high CO2 sorption capacity was due to the availability of oxygen vacancy in CeO2, which could accelerate the CO2 diffusion through product layer during the carbonation reaction. Meanwhile, the superior CO2 cyclic sorption stability was ascribed to the highly dispersed CeO2 in CaO sorbents, which could inhibit the sintering of CaO.

Promotional effect of CeO2 on CO2 cycling performance of CaO based adsorbents

ACS Spring Meeting 2021

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