Interaction of Pristine Hydrocalumite-Like Layered Double Hydroxides with Carbon Dioxide.

The layered double hydroxides (LDHs) of Ca and trivalent cations, Al and Fe, are single-source precursors to generate supported CaO, which picks up CO from the gas phase in the temperature range 350-550 °C. The supports are ternary oxides, mayenite, and CaFeO. The uptake capacity of the Fe-containing LDH at 1.9 mmol g is two times the capacity of the Al-containing LDH. The product of CO uptake is calcite CaCO. It is observed that the intercalated chloride ions reduce the thermal penalty by inducing the early decomposition of CaCO. In the case of the chloride-intercalated LDHs of Ca and Fe, the CaCO formed is completely decomposed at 900 °C. This is in contrast with the CaCO formed from bare CaO, which shows no sign of decomposition at 900 °C under similar conditions. This work shows that the hydrocalumite-like LDHs are candidate materials for CO mineralization.