Screening of metal oxides to promote CO₂ adsorption performance over polyethyleneimine incorporated solid adsorbents

Amine-modified solid sorbents have attracted extensive interests in post-combustion carbon capture for power plants. Among various amines, polyethyleneiemine (PEI) is likely to be the most effective and promising candidate. However, previous studies have mainly focused on examining various supports to increase PEI loading and then enhance CO2 adsorption capacity. In this study, one rare earth element (Ce) and 6 first-row transition metals (from V to Cu) in the oxidation states impregnated on PEI incorporated γ-Al2O3 were prepared and investigated as potential catalyst/promotor for base-catalyzed reaction. Thermodynamic analysis, including isothermal and quasi-static CO2 adsorption tests, were implemented to evaluate the performances amongst the 7 metal oxides. The results showed that MnO2, CeO2 and Fe2O3 showed a better performance in isothermal CO2 adsorption at 75^oC. Upon quasi-static tests, the results also indicates that the peak adsorption temperatures (Tpeak, a) of V2O5 and Cr2O3 shifted to high temperature region, whilst opposite behavior of MnO2 was observed. In preliminary study, density functional theory (DFT) was also adopted to assist the screening of metal oxide in terms of bond length and adsorption energies.