Sorption-enhanced CO capture over Cu-Mn-Ce composite oxides with LiOH addition: CO oxidation and in-situ CO2 sorption

Abstract

CuO-MnOx-CeO2 composite catalysts coupled with different amounts of LiOH sorbent were prepared using a solid-state impregnation method and characterized by XRD, N2 adsorption, FE-SEM/EDS and ICP-OES. Then the samples were tested dynamically and isothermally for CO capture involving CO oxidation and CO2 sorption reactions in the temperature range of 30–180 °C under the dry and wet conditions. The results showed that the samples were able to catalytically oxidize CO and chemically absorb CO2 in situ at low temperature. Particularly, CuMnCe/10LiOH exhibited the higher CO oxidation activity than the traditional CuO-MnOx-CeO2 catalyst, and significantly the resistance to water vapor of the sample was also promoted. Isothermal CO2 capture experiment results further revealed that CuMnCe/LiOH could achieve the larger CO2 sorption efficiency by the in-situ way when compared with trapping CO2 diluted in the feed gas. The promoted CO catalytic performance with the excellent tolerance to water poison, and the higher CO2 sorption capacity and efficiency, could be attributed to the synergistic interaction between the CO catalyst and the CO2/H2O sorbent induced by the sorption and transfer of the intermediate gases CO2 and H2O, which modified the influences of two-sidedness CO2 and H2O gases on CO oxidation and CO2 sorption reactions, respectively. These were summarized as a novel concept called Sorption-Enhanced CO Capture (SECC).